Seaweeds of the South African South Coast

Book 1: General Introduction
and
Phylum Chlorophyta (Green Seaweeds)

By

Robert James Anderson
University of Cape Town and Department of Agriculture, Forestry and Fisheries, South Africa

Herre Stegenga
Naturalis, Netherlands

John Joseph Bolton
University of Cape Town, South Africa

2018

Herre Stegenga's line drawings from Seaweeds of the South African West Coast
(Contributions from the Bolus Herbarium, Vol 18, 1997) are reproduced with permission.  

Copyright © 2018 Robert Anderson et al. All rights reserved.

Copyright © 2018 by Robert Anderson et al.
All rights reserved. No part of this publication
may be reproduced, distributed, or transmitted in any
form or by any means, including photocopying, recording,
or other electronic or mechanical methods,
without the express written permission of the authors
except for the use of brief quotations in a book review.

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First Edition, 2018

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GENERAL INTRODUCTION TO THE SOUTH COAST

This guide covers the seaweeds (marine macro-algae, excluding the crustose corallines) of approximately 1000 km of coastline, from Cape Agulhas to the Umtamvuna River (the border between the Eastern Cape and KwaZulu-Natal provinces). This is largely a discrete biogeographic area and includes the entire Agulhas Marine Province as well as some of the overlap zone with the KwaZulu-Natal flora. However, the seaweeds of the south coast have not been comprehensively documented, although there is some overlap with existing publications for the west coast (Stegenga et al. 1997) and Kwazulu-Natal (DeClerck et al. 2005.To make this account as complete as possible, we include the species that are already covered in those books.

Users of this guide are reminded that continuing studies will lead to changes in systematics and the names of some seaweeds, but that these can be checked on the excellent website AlgaeBase.org.

We have tried to make the guide as complete as possible, to the extent of including taxa that do not fit any current descriptions (e.g. as sp. 1, sp. 2,). To have studied these further would have prevented us from ever finishing, and our information on these taxa should nevertheless be useful to other phycologists (those who study algae).

Descriptions are based on existing literature and examinations of specimens and microscope sections. Illustrations are our own photographs of specimens or microscope slides, and where appropriate, scans of Herre Stegenga’s excellent drawings from ‘Seaweeds of the South African West Coast’. In a few cases we re-drew illustrations from other publications.

Note on format and structure

This guide is in a number of sections. The main (systematic) sections are in the customary order of Green, Brown and Red Seaweeds. Within each of these, genera are arranged by Order and Family, but no descriptions of these higher taxa are provided. Genera are briefly described when they contain two or more species, with a key to the species. Full descriptions and illustrations are then given for each species. Taxonomic terms are explained in the Glossary, and references are included under each species.

THE COASTAL ENVIRONMENT

We follow Bolton and Stegenga (2002) in dividing the coast of South Africa into 50 km sections for the purpose of plotting seaweed distributions: the south coast (Figure 1 and Table 1) falls between section 22 (Cape Agulhas area) and section 48 (Mzamba to Margate). Seaweed distributions are interpolated: that means that if a species is found for example in sections 35 and 37, it is assumed to also occur in section 36. However, for most species we also state the actual places at the extremes of their recorded ranges.

The south coast
Figure1. The south coast, with every second 50 km section numbered. See Table 1 for boundaries.

The south coast
Figure 1b. The South African south coast, with place names commonly used in species distributions

Table 1. The 50 km long coastal sections used by Bolton & Stegenga (2002) that fall within the south coast, as defined in the present study. Numbers, with geographical coordinates, positions of boundaries relative to known places, and some well-known sites included in each section, as in Bolton & Stegenga (2002).

No.

South

East

Boundaries

Sites included

23

20.47732

-34.49243

Struisbaai -Skipskop

Struisbaai, Arniston

24

20.87056

-34.38810

To just E of Cape Infanta

Koppie Allen, Infanta, Witsand

25

21.35563

-34.42480

To just E of Jongensfontein

Puntjie, Skurwe Bay

26

21.82968

-34.38157

To just W of Gouritzmond

Stilbaai, Bloukrans, Bull Point

27

22.11571

-34.15734

To just E of Mossel Bay

Gouritzmond, Vleesbaai,

28

22.53969

-34.01308

To just W of Victoria Bay

Hartenbos, Grootbrak, Herolds Bay

29

23.01642

-34.07989

To just W of Knysna Heads

Victoria Bay, Wilderness, Walker Bay

30

23.35867

-34.10201

To just W of Plettenberg Bay

The Heads, Neusgate

31

23.78027

-34.00998

To Elandsbos River

Plettenberg Bay, Keurbooms,

32

24.26944

-34.08458

To Skuinsklip

Storms River, Voelkrans, Skietgate

33

24.73894

-34.18988

To Thyspunt

Tsitsikamma River, Klipdrif River

34

25.03553

-34.97130

To just W of Gamtoos River

Cape St Francis, Jeffreys Bay

35

25.51952

-34.03581

To just E of Sardinia Bay

Van Stadens River, Claasen Point

36

25.69996

-33.79133

To just E of St Georges Beach

Chelsea pt, Port Elizabeth, Bluewater

37

26.17661

-33.72051

To just W of Woody Cape

St Croix Is., Sundays River

38

26.64813

-33.70001

To just W of Kenton-On-Sea

Bird Is., Cape Padrone, Cannon Rocks

39

27.10371

-33.52269

To just E of Kleinemonde

Kasouga, Port Alfred

40

27.51706

-33.26662

To just E of Keiskamma River

Great Fish River, Madagascar Reef

41

27.92591

-33.01227

To just E of East London

Kayser’s Beach, Cove Rock

42

28.30072

-32.73128

To Haga-Haga

Gonubie, Cintsa

43

28.68348

-32.43986

To Qora River

Morgan bay, Kei Mouth, Mazeppa Bay

44

29.04811

-32.11370

To just E of Xora River

Dwesa, The Haven

45

29.37234

-31.76221

To Sharks Point

Mncwasa river, Coffee bay, Hluleka

46

29.74337

-31.46446

To Mkozi River

Bolder Bay, Port St Johns, Montshe, Ntsubane

47

30.12123

-31.17581

To Mnyameni River

Cathedral Rock, Lambasi Bay,

Coastal topography
The outline of the south coast was created during the fragmenting of Gondwanaland, which started some 135 million years ago. Rock types along the coast vary with geological history, and include sandstones, dolerites, shales and aeolianite (Marker, 1988). These vary in hardness and texture, and result in a variety of shapes of shores and of the rocks themselves, creating a corresponding variety of habitats for marine life in the inshore zone.

The rocky and sandy shores of South Africa were charted by Jackson &amp; Lipschitz (1984) and a further but important shore-type (mixed shores of sand and rock) was quantified by Bally et al (1984). The south coast as we define it here displays varying coastal geology and topography and contains elements of all of these shore types.

From Cape Agulhas to Algoa Bay, rocky capes (e.g . Cape Agulhas, Cape Infanta, Cape St Blaize, Cape Seal, Cape Recife ) form exposed headlands that create half-heart bays on their eastern sides. Between these bays lie smaller headlands, stretches of sandy beach, and wave-cut platforms of hard rock or softer aeolianite (good examples of the last type are found at De Hoop and west of Stilbaai). This part of the coast has few, but relatively large rivers and estuaries. From Cape Padrone eastwards the pattern of half-heart bays is replaced by an undulating coastline with many small (and a few large) estuaries. East of Port Alfred the proportion of sandy shore falls: there are many stretches of wave-cut platform interspersed with small beaches. From East London eastwards the coast is dominated by relatively low wave-cut platforms interspersed with coarse-grained sandy beaches, with notable areas of rocky headland around Hole-in-the-Wall, Brazen Head, Port St Johns, and Waterfall Bluff. From there to the Umtamvuna River the coast comprises extensive wave-cut platforms with short stretches of coarse-grain sandy beaches.

Many of the small estuaries, particularly on the eastern part of this coast, are only open sporadically or seasonally, and estuaries probably have little influence on seawater salinity or the seaweeds along this coast. The Knysna Estuary is large enough to form a substantial habitat of its own, but has a relatively small catchment area and little influence on the outer coast.

Climate
The terrestrial climate ranges from temperate in the west to subtropical in the east, with a corresponding change in the seasonality of rainfall. Along the coast from Cape Agulhas to the Bushmans River area, rain falls mainly in winter, but also with peaks in spring and autumn, while from East London eastward most rain falls mainly in spring and autumn, with fairly high summer rainfall and little in winter. Low pressure systems that bring most of the rain to the Western Cape and southern part of the south coast tend to weaken by the time they reach the Port Elizabeth area.

This is a very windy coast, especially between Port Elizabeth and the East London area, and the winds strongly affect seawater temperatures, both on broad and very localized scales (see later).

Tides and waves
Tides along the South African coast are diurnal (there are two low and two high tides per day), with a maximum range of about 2m during the spring tide periods. Tidal range peaks during spring tides, so that Low Water Spring tides (LWS) are the best times for collecting seaweeds in the intertidal zone.

The south coast is exposed to large and frequent swells that arrive mainly from the south west, but at times strong southerly and south east winds may produce large swells from those directions. Wave effects are reduced within bays, but in general this coast is very exposed.

Inshore sea temperatures and coastal currents
The single most important factor that controls the geographical distribution of most marine organisms is water temperature. This is because metabolic processes are controlled by temperature, and each species has a genetically determined range of temperatures within which it can live. Whether an organism can breed, thrive, or even just survive at a particular temperature is laid down in its genes. In the case of seaweeds, many studies have demonstrated the controlling effects of temperature on geographical range (e.g. Breeman 1988; L&uuml;ning 1990). For this reason we discuss seawater temperatures along the south coast in some detail.

While average seawater temperatures (for example, over a year) may sometimes be useful in explaining distributions, it is often the extremes and their durations that are more important. All of these are controlled by a number of factors that operate at various scales. For a recent account of inshore seawater temperatures around the coast of South Africa, see Smit et al. (2013).

Major ocean currents operate at the largest scale, and the south coast is overwhelmingly affected by one of the world&rsquo;s greatest among these: the Agulhas Current. This powerful ocean current originates in the western Indian Ocean by the confluence of the Mozambique Current (flowing south between Mozambique and Madagascar) and the South Equatorial Current (flowing westwards below Madagascar, then turning south).

The Agulhas Current is one of the largest in the world, up to 100 km wide and 1000m deep, and reaching speeds of up to 3.5 m s⁻¹. Its average surface temperature falls as it travels south-westwards along the south coast, from about 23oC off Port St Johns to about 20 oC off Cape Agulhas. However, although this current brings warm water to the coast as a whole, it runs along the edge of the continental shelf , which varies in its distance from the shore, and inshore water temperature are affected by other processes, the most important of which are various types of upwelling.

Upwelling describes the movement of water from deeper to shallower levels (usually to the surface) and invariably results in cooling of the surface water, simply because the deeper water is colder (cold water sinks) and also because shallow water has been heated by the sun. Deeper water usually contains more nutrients so that upwelling is often essential to sustain primary production of autotrophs in the inshore zone.

Several types of upwelling affect the south coast (Lutjeharms et al. 2000) and together they strongly affect the distribution and productivity of the seaweeds.

Upwelling between the continental slope and the shoreward side of the Agulhas Current, which is typical of the inshore side of Western Boundary Currents such as the Agulhas.

Wind-induced upwelling that is associated particularly with headlands, and operates during prolonged easterlies.

Upwelling where shear-induced eddies along the edge of the continental shelf carry cold water in their cores and this cooler water moves onto the Agulhas Bank and ultimately lowers inshore water temperatures.

Upwelling associated with areas where the width of the coastal shelf increases. This type (see Lutjeharms 2000) is particularly important on the south coast. Its influence, which is felt about 45% of the time, extends from Algoa Bay to Mbashe, and is strongest in the Port Alfred area. The core temperature of these upwelling cells is up to 11 oC cooler than the surface water of the Agulhas Current and more than 5 oC cooler than adjacent shelf water. The result is that the average inshore sea temperatures in this area remain fairly similar over several hundred kilometers and do not rise consistently from west to east (Figure 2).

Figure2. Inshore seawater temperatures for each 50 km section of the South African coast (W to E). Data from in situ recorders and measurements, interpolated in some sections. Max and min are means of warmest and coldest months. (Smit, Anderson & Bolton, in prep.).

Nutrients

The two most important macro-nutrients for seaweeds are generally considered to be Nitrogen (N) and Phosphorus (P), and these and other macro-and micro-nutrients are mainly provided by the upwelling of cool, nutrient-rich water from the continental shelf or deeper. The nutrients come mainly from decomposed organisms that have sunk down to the sea-floor, although riverine sediments also contribute organic matter that is ultimately upwelled in the form of inorganic nutrients.

Nutrient levels vary temporally and spatially in inshore waters of the south coast, and in general are probably inversely related to water temperature, as shown for the Benguela system (Waldron &amp; Probyn 2010). There, temperatures below about 16 oC usually indicate moderate to high nutrient levels, while those above 18 oC indicate low or limiting levels. Water temperature can thus serve as a general indicator of nutrient availability.

ECOLOGY

Intertidal zonation

Most studies of intertidal seaweed communities on the south coast are general descriptions that focus on zonation patterns. Zonation schemes for seaweeds and animals on south coast rocky shores (Brown & Jarman 1978; Branch & Branch 1981) are based on the pioneering studies of Stephenson (1944) and Stephenson & Stephenson (1972).

Briefly, a typical south coast rocky shore shows a number of fairly distinct zones (see for example, Branch et al. 2010). However, the vertical height and composition of these zones is strongly influenced by a number of factors, especially wave exposure and the presence of sand. The following account is based in the middle of the south coast, in the Port Elizabeth area, and the component species change towards the eastern and western extremes of this coast.

The supralittoral (essentially the spray zone during high tides) is characterized by numerous small Littorinid snails and occasional patches of (usually pale, yellowish) Porphyra, with mats of Bostrychia in crevices and overhangs. Below this the upper eulittoral is characterized by barnacles, limpets, the snail Oxystele and low, scattered patches of various seaweeds including Ulva, Caulacanthus, Splachnidium and sometimes turf-like patches of very small Gelidium pristoides. The mid-eulittoral is often distinguished by a high cover of encrusting coralline algae (especially in hollows), the snail Oxystele tigrina, various limpets (especially Scutellastra longicosta and S. oculus) and sometimes extensive patches of the reef-worm Pomatoleios. A number of seaweeds are found, usually in mixed, low turfs, but Gelidium pristoides may be common to dominant, growing attached to rock, limpet shells, and Pomatoleios tubes. On wave-exposed shores the lower eulittoral is usually dominated by Scutellastra cochlear, with a high cover of crustose corallines, and upright seaweeds limited to crevices ( e.g. G. pristoides, Laurencia flexuosa, Hypnea spicifera). At very exposed sites, or those influenced by sand, this zone is instead often dominated by beds of mussels. The sublittoral fringe may bear a high cover of encrusting corallines and extensive beds of seaweeds, especially species such as Plocamium cornutum, Plocamium corallorhiza, Laurencia flexuosa, Hypnea spicifera, and notably, prominent beds of mixed articulated corallines (Amphiroa, Arthrocardia, Jania). This zone can also bear beds of Pyura, which largely exclude seaweeds.

A general scheme such as this can be greatly modified by moderate sand influence, which excludes many of the animals and tends to produce a lower eulittoral zone/sublittoral fringe completely dominated by a low compact turf of articulated coralline algae that covers either bare rock or a thin layer of encrusting coralline. On wave-sheltered shores zonation is vertically compressed, and some zones (e.g. that of Scutellastra cochlear) may be absent or insignificant.

The sublittoral zone

There are only two studies of subtidal seaweed communities on the south coast: that of Anderson & Stegenga (1989) at Bird Island, near Port Elizabeth, and an unpublished MSc study of shallow subtidal communities at eleven sites between Stilbaai and Mzamba (Wilby 2009).

The shallow sublittoral zone of the south coast (0-3m) is dominated by a mixed community in which more than 50% of the wet biomass is contributed by articulated coralline algae of the genera Amphiroa, Arthocardia and Jania. Significantly, most of the larger fleshy algae belong to genera known for the production of grazer-deterrent chemicals (e.g. Caulerpa, Laurencia and Plocamium). The implication is that grazing has a large effect in structuring these communities, and an investigation of the roles of different suites of herbivores (especially fish) is long overdue.

Diving observations and the study of Anderson & Stegenga (1989) at Bird Island show that below 2-3 m depth, algal biomass generally declines with depth, as might be expected on a coast where the water is often fairly turbid. In our experience the deepest reasonably substantial stands of upright seaweeds are found around the 15-20m mark, and it is only on offshore seamounts and reefs, where the water is usually clear, that substantial beds may be found at even 40-50m depth. Generally, as one dives deeper than a few m below MLWS, algae are progressively replaced by filter feeders (e.g. sponges, ascidians, etc.).

BIOGEOGRAPHY

Biogeography is the study of the patterns and causes of the geographical distribution of an organism or group of organisms. Knowing what grows where is important for conservation and helps us to understand how the broader ecosystem might work, and will help us to measure and perhaps predict the effects of climate change.

SA coast biogeographical provinces
Figure3. The coast of southern Africa showing seaweed marine biogeographical provinces (from Anderson et al. 2009).

The South African coast spans a range of inshore temperature regimes, from the tropical waters of northern Kwazulu-Natal to the cold waters of the west coast, with a corresponding change in the biogeographical affinities of the organisms that inhabit this coast. Based on a study of 318 common species (including 116 seaweeds), Stephenson (1948) divided the coast into three biogeographic provinces: the cold temperate west coast, the warm temperate south coast, and the subtropical east coast. Subsequent studies have refined his concepts of general biogeographic divisions (see for example Lombard et al. 2004), and different groups of organisms sometimes show somewhat different biogeographic patterns, but our current understanding of seaweed distributions indicates three distinct biogeographic provinces, with overlap regions between them (see Figure 3).

The Agulhas Marine Province covers most of the coast we are dealing with here, and extends from Cape Agulhas ( a fairly distinct boundary)to a broader and less distinct boundary area in the eastern part of the Eastern Cape Province: probably around the central-northern Transkei. Its western overlap is with the cool-temperate Benguela Marine Province, and extends from Cape Agulhas to about Cape Point. Its eastern overlap zone is more difficult to define. From the northern Transkei running up through Kwazulu-Natal, the south coast seaweed flora, with its high percentage of endemics, is gradually replaced by species with tropical affinities (Bolton et al. 2004): north of Cape St Lucia the flora is overwhelmingly Indo-West Pacific in nature. Very few seaweeds are endemic to the southern and central Kwazulu-Natal coast (around 2% of total species), which is one of the reasons to regard it as a transition zone rather than a biogeographic province (Bolton et al. 2004).”

Seaweed communities change from east to west within the Agulhas Marine Province, with sub-regions detectable in terms of presence/absence of species (Anderson et al. 2009). A primary division in the Port Alfred/Great Fish River area indicates some difference between the western (cooler-water) and eastern (warmer-water) communities. This, and further (lower-level) subdivisions in seaweed distributions were used by Anderson et al. (2009) to assess the effectiveness of Marine Protected Areas on this coast.

COMMERCIAL SEAWEEDS

The south coast is notable for its commercial quantities of the intertidal red seaweed Gelidium pristoides, which has been harvested there since the 1950s for the extraction of agar (Anderson et al. 1989). The agar is of a high quality, and the content varies between 30 and 48% of dry weight (Carter & Anderson 1986). Harvesting is done during Low Water Spring (LWS) tides, by labourers who walk slowly over the rocks and pick the largest tufts by hand. About 100 t dry weight of Gelidium (mainly G. pristoides, but also small amounts of G. pteridifolium and G. abbottiorum) is collected annually between Kei Mouth and Cape St. Francis. The effects of this harvesting on G. pristoides and other intertidal organisms has been investigated and shown to be ecologically minimal (see review by Anderson et al. 1991). The other two species are mainly found in the sublittoral fringe and shallow sublittoral zone, and so the commercial harvesting from the intertidal zone is thought to have little effect on their populations as whole.

INTRODUCTION TO THE CHLOROPHYTA

The phylum Chlorophyta (commonly known as the green algae) includes a very large range of living things, growing in all ecosystems where there is light. Many of them are microscopic, single-celled organisms, very common in freshwater and the sea, and there are also terrestrial green algae which are common, for example, on damp rocks and bark of trees. Among the algae, the Chlorophyta are most closely related to flowering plants, and green plants in general have many characteristics in common such as similarities in their chemistry (e.g. photosynthetic pigments, cell wall composition, storage compounds). In evolutionary terms, the green algae are more closely related to the land plants than they are to red and brown algae.

The green marine macroalgae (seaweeds) occur on all rocky seashores, throughout the world, although there are generally fewer species than red algae. Most species in South Africa are placed in 6 globally widespread genera (Ulva, Cladophora, Chaetomorpha, Bryopsis, Caulerpa, Codium). Species in many of these groups are very difficult to tell apart without close microscopic examination. Their taxonomy is in a state of flux, and until all these genera have been studied in detail on a global scale, including modern DNA sequencing methods, names are likely to change in the near future.

The green seaweeds range in size from almost microscopic threads on the surface of other seaweeds, to large plants which may be more than 1m in length (e.g. Codium platylobium). Some species, particularly in the genera Ulva and Chaetomorpha, grow especially in habitats with high nitrogen content such as estuaries affected by humans and upper shore rock pools affected by bird guano. Some groups of green algae have an unusual construction with no separate cells, and are made up of tubes consisting of an outer cell wall containing millions of nuclei and chloroplasts (the siphonous greens such as Codium, Caulerpa, Halimeda etc.). Others are branched or unbranched single rows of cells (e.g. Chaetomorpha, Cladophora) or flat sheets of cells (e.g. Ulva).

In South Africa, large amounts of the green seaweed Ulva are grown on certain abalone farms as a feed for the valuable mollusc Haliotis midae (perlemoen). This animal is the main product of marine aquaculture in South Africa, with 1300 tonnes per year grown in ponds on land, using pumped sea water. On some farms the effluent-water is run through large, round-ended raceway ponds, in which the Ulva is grown. (Troell et al. 2006, Bolton et al. 2008). A large proportion of the South African Ulva production takes place at one farm on the south coast, Wild Coast Abalone in Haga Haga.

SYSTEMATIC CLASSIFICATION OF SOUTH COAST CHLOROPHYTA

Order Ulotrichales

ULOTRICHACEAE

Ulothrix flacca

Order Chaetophorales

CHAETOPHORACEAE

Sporocladopsis novae-zelandiae

Order Ulvales

KORNMANNIACEAE

Blidingia minima

ULVACEAE

Letterstedtia insignis
Ulva clathrata
Ulva compressa
Ulva fasciata
Ulva flexuosa
Ulva intestinalis
Ulva prolifera
Ulva rhacodes
Ulva rigida
Ulva torta
Ulva uncialis

ULVELLACEAE

Acrochaete sp.

Order Cladophorales

CLADOPHORACEAE

Chaetomorpha aerea
Chaetomorpha antennina
Chaetomorpha linum
Chaetomorpha natalensis
Chaetomorpha spiralis
Chaetomorpha vieillardii
Cladophora albida
Cladophora coelothrix
Cladophora flagelliformis
Cladophora lehmanniana
Cladophora radiosa
Cladophora rugulosa
Cladophora sericea
Cladophora sp. 1
Cladophora sp. 2
Rhizoclonium riparium
Willeella ordinata

Order Siphonocladales

SIPHONOCLADACEAE

Chamaedoris auriculata
Chamaedoris delphinii

VALONIACEAE

Valonia aegagropila
Valonia macrophya

Order Bryopsidales

BRYOPSIDACEAE

Bryopsis africana
Bryopsis caespitosa
Bryopsis hypnoides
Bryopsis myosuroides
Bryopsis plumosa
Bryopsis pusilla

CAULERPACEAE

Caulerpa bartoniae
Caulerpa brachypus
Caulerpa filiformis
Caulerpa holmesiana
Caulerpa racemosa
Caulerpa zeyheri

CODIACEAE

Codium capitatum
Codium duthiae
Codium extricatum
Codium fragile subsp.capense
Codium incognitum
Codium isaacii
Codium lucasii subsp. capense
Codium megalophysum
Codium papenfussii
Codium pelliculare
Codium platylobium
Codium pocockiae
Codium prostratum
Codium spongiosum
Codium stephensiae
Codium tenue

HALIMEDACEAE

Halimeda cuneata
Halimeda tuna

PSEUDOCODIACEAE

Pseudocodium devriesii

UDOTEACEAE

Udotea orientalis

DERBESIACEAE

Derbesia hollenbergii
Derbesia marina

PICTURE GUIDE TO GENERA OF SOUTH COAST GREEN SEAWEEDS

Ulva (and Letterstedtia): foliaceous, flat membranous or cup-shaped or tubular, blade 2 cells thick when flat, one cell when tubular. Chloroplasts single, parietal, with one to several pyrenoids.
Eleven species on south coast.

Bryopsis: tubular, coenocytic (no cross-walls), filamentous, main axes and short branches, gametes in unmodified branches.
Six species on south coast.

Cladophora: uniseriate filamentous, multicellular, branched, axes free, erect, filaments at least 20 µm wide.
Ten species on south coast.

Chaetomorpha: filamentous, unbranched, only basal cell attached or sometimes in floating mats, filaments over 100 µm diameter.
Six species on south coast.

Rhizoclonium: multicellular filaments up to 60 um diameter, forming loose mats, filaments sometimes with rhizoidal branches.
One species on south coast.

Derbesia/ Halicystis: sporophytes coenocytic, filamentous, sparsely branched, sporangia on double-walled pedicel. Halicystis stage ovoid/spherical.
Two species on south coast.

Caulerpa: coenocytic, horizontal stolons with erect fronds of various shapes.
Six species on south coast.

Codium: thalli of utricles (inset) united into spongy structures of various shapes, gametangia lateral on utricles.
Sixteen species on south coast.

Pseudocodium: thalli soft, branched, core of siphons with cortex of utricles, gametangia developing from medullary siphons.
One species on south coast.

Halimeda: thalli jointed, calcified, branched, gametangia on surfaces of segments.
Two species on south coast.

Udotea: flat, stiffish (calcified) blades on stalks, thalli to ca 3cm tall, filamentous internal structure, blades with concentric growth lines.
One species on south coast.

Chameadoris: thallus brush-like, capitulum (head) of adherent siphons borne on unbranched stipe.
Two species on south coast

Valonia: thallus of large (1-35 mm diameter) cells forming cushions a few to 20 cm in daimeter.
Two species on south coast.

Sporocladopsis: epiphytic, forming green to black velvety cushions on large algae. Comprising mat of multicellular filaments.
One species on south coast.

Blidingia: pale green tubular thalli up to 5 cm tall, walls one cell thick, chloroplasts stellate with single central pyrenoid.
One species on south coast.

Acrochaete: thallus microscopic, comprising unseriate filaments creeping in cell walls of larger algae. Cells with single parietal, reticulate chloroplast.
One species on south coast.

THE CHLOROPHYTA

Order Ulotrichales

Family Ulotrichaceae

Ulothrix flacca (Dillwyn) Thuret in Le Jolis 1863: 56

Filaments attached by rhizoidal extensions from a few proximal cells, plants of rather indeterminate length. Growing by scattered intercalary divisions, at the same time the apical portion continually sloughing off in the process of spore formation. Filament diameter (10-) 12 -18 µm, the cells 0.2-1.0 times longer than broad, slightly longer in the proximal part. Cells with a single parietal girdle-shaped chloroplast and mostly one pyrenoid. Plants becoming reproductive in the distal part, sporangial (or gametangial) cells approximately isodiametric; forming 4-8 zooids.

Description from Stegenga et al. (1997).

Collections, ecology and regional distribution

Recorded from the west side of the Cape Peninsula to Knysna (16-30). Usually found in the supralittoral, also in brackish habitats. Epilithic and epiphytic.

World distribution: Widespread in temperate regions (Guiry & Guiry 2012).

Type locality: Swansea, Wales (Guiry & Guiry 2012).

Ulothrix flacca. 1. Part of basal filament. 2. Upper part of filament with zooidangia. Reproduced from Stegenga et al. (1997).

Order Chaetophorales

Family Chaetophoraceae

Sporocladopsis novae-zelandiae Chapman 1949: 496, fig. 4

Plants forming a dark green to almost black velvety cover on large algae. Structure of irregularly branched prostrate filaments producing short multicellular rhizoids penetrating the substrate, and many erect filaments of remarkably uniform length. Erec axes of two types: (1) a tightly compact layer of short filaments, 50-150 µm high and (2) a layer of lower density consisting of longer filaments (up to 600 µm long). Filaments 10-15 µm in diameter, cells 1-2 times longer than broad, with a single parietal chloroplast and one or two pyrenoids. Sporangia formed terminally on short filaments; ovate or club-shaped, 20-30 x 10-12 µm, producing 8-16 spores. (Description from Stegenga et al. 1997).

Collections, ecology and regional distribution

Recorded from Yzerfontein on the west coast to Mkambati (14-47). Growing on larger algae such as Ecklonia maxima, E. radiata, Sargassum spp. and Gelidium abbottiorum.

World distribution: Also found in Argentina, Australia and New Zealand (Guiry & Guiry 2012).

Type locality: New Zealand (Chapman 1949).

Note: Stegenga et al. (1997) point out that the name Pilinia may have been misapplied to this entity in South Africa: this belongs to a brown alga.  

Sporocladopsis novae-zelandiae, cushions on wet stipe of Ecklonia radiata, Qolora, Transkei. Stipe about 15 mm in diameter.

Sporocladopsis novae-zelandiae, cushions drying on stipe of Ecklonia radiata, Qolora, Transkei. Stipe about 15 mm in diameter.

 Sporocladopsis novae-zelandiae. XS of Ecklonia radiata stipe showing two layers of Sporocladopsis filaments: short dense layer and layer of long, sparse filaments

Sporocladopsis novae-zelandiae. Detail of fertile material (stained slide) showing junction of inner short layer with some sporangia, and longer outer filaments.

Sporocladopsis novae-zelandiae. Cross-sections of thalli, in Fig. 2 with sporangia (rows of epidermal cells of substrate, Ecklonia maxima, dotted). Illustration from Stegenga et al. 1997.

Order Ulvales

Family Kornmanniaceae

Blidingia minima (Nägeli ex Kützing) Kylin 1947: 181

Plants pale green, tubular, up to 5 cm tall. Thalli narrowly linear below, gradually expanding upwards to a width of about 5 mm, rarely branched. Cells in surface view in no definite order, (rounded) angular, 4-8 µm in largest diameter. Thallus membrane 8-10 µm thick, cells 6-7 µm high, approximately square. (Description and illustration from Stegenga et al. 1997).

Collections, ecology and regional distribution

Found in the upper eulittoral and supralittoral fringe, both in rock pools on exposed coasts and on salt marsh plants. Recorded from Langebaan Lagoon on the west coast to the Morgan Bay area (13-43).

World distribution: widespread in temperate waters (Guiry & Guiry April 2012).

Type locality: Helgoland, Germany (Silva et a.l 1996).

Blidingia minima. 1. Habit. 2 base of plant. 3 Surface view of thallus showing cell arrangement and stellate chloroplasts. 4 Cross section. Illustration from Stegenga et al. (1997) (Herre Stegenga).

Order Ulvales

Family Ulvaceae

Letterstedtia insignis Areschoug 1850: 2, pl. I

Plants dark grass-green in young parts grading to pale yellow in central part of fronds, 20-50 cm tall, texture flexible in young parts to stiff in older basal parts; thallus shape varying from bushy with deeply incised fronds to many narrow strap-shaped fronds with marginal frills or leaflets; marked thickening in midrib and basal area; holdfast callus-like, up to 2 cm in diameter, bearing one to several distinct fronds. Lamina ca. 75-100 µm thick, comprising two cell layers with their inner walls in close contact and sometimes partly fused; in cross section cells near edge of lamina ca. 30 µm high x 16 µm broad. In surface view cells ca. 15-20 µm in diameter, angular. Thickening of midrib and basal region of thallus produced by separation of two cell layers by trabeculae interspersed with thick-walled rhizoids. Growth from diffuse meristematic tissue in all young parts of frond. Holdfast with central zone of rhizoids growing down from between two cell layers, re-inforced by trabeculae and wall substance, enclosed by callus extending up lower thallus. Reproduction in any young parts of fronds; fertile areas clearly delimited within zones of thick-walled vegetative cells; after shedding of gametes, transparent evacuated areas of tissue sloughed off.

Collections, ecology and regional distribution

Recorded from Port Alfred to Durban (39-51) but see note below. Reported to occur in the shallow eulittoral and littoral fringe, but see note below.

World distribution: Also reported from New Zealand (Broady et al. 2012).

Type locality: near Port Natal (Durban), South Africa (Pocock 1959).

Notes:

1. Letterstedtia is distinguished from Ulva by having: a complex morphology (various types of blade appendages), a massive holdfast and wart-like callus, thickening involving rhizoids and transverse trabeculae, frills on the blade straps, and reproduction in any meristematic region.

2. Despite Pocock having made repeated collections (there are many specimens in GRA) of this species from Salt Vlei (near the Kowie mouth) and Waterloo Bay, and the existence of herbarium specimens from other locations in the Eastern Cape, we have repeatedly searched for it in the former two locations but never found it. Interestingly, Pocock records that it although the type locality is Durban Bay, it was never subsequently found there. However, we collected a small specimen in Nature’s Valley (D77) that may belong to this species, based on the thickened midrib area with trabeculae, frilled frond margins and arrangement and size of cells (see illustrations of specimen D77).

Letterstedtia insignis, Port Alfred (herbarium specimen, BOL)

Letterstedtia insignis, Port Alfred, basal region and holdfast (herbarium specimen)

Letterstedtia insignis, Port Alfred, mid-upper region (herbarium specimen, BOL)

Letterstedtia insignis? Nature’s Valley, specimen D77, fresh material – see note

Letterstedtia insignis? Nature’s Valley, surface view of cells, some dividing, specimen D77, fresh material – see note

Letterstedtia insignis. XS through midrib showing trabeculae and rhizoids (slide specimen EC 2017)

Letterstedtia insignis, showing minute teeth on apical margin of a blade (slide specimen EC 2169)

Order Ulvales

Family Ulvaceae

Ulva Linnaeus

Mature thallus flattened or tubular/hollow. In the former comprising two cell layers, in the latter comprising a single cell layer (including most species formerly assigned to Enteromorpha). Thalli variously shaped, sometimes perforated or with dentate margins. Growth mainly by marginal cell division. Attachment by rhizoidal cells. Rhizoidal cells running between layers of blade in basal region of thallus. Life history usually comprising alternation of isomorphic diploid sporophytes (producing asexual, quadriflagellate zoospores) and haploid gametophytes (producing biflagellate gametes), but parthenogenesis recorded in some species.

The genus Ulva formerly consisted of entities with distromatic blades and the genus Enteromorpha of entities with tubular monostromatic thalli. However, Hayden et al. (2003), using molecular methods, showed that they cannot be separated at the generic level, and the older name, Ulva, now applies.

Over 500 species have been described, mainly based on thallus shape and size, but studies have shown that these characters are strongly affected by environmental conditions. At present some 98 species are accepted (Guiry & Guiry, 2012), of which we recognize 11 on the South African south coast. Current molecular studies indicate that several of the names we apply here are likely to change, but for the time being we base our descriptions on existing morphological understanding, and largely follow Stegenga et al. (1997).

Records of several species of Enteromorpha/Ulva from the South African south coast are for various reasons difficult to substantiate, and we have not attempted to document them here. Enteromorpha bulbosa (Suhr) Montagne was recorded by Barton (1893), but not reported since. E. lingulata J.Ag. was recorded from Hluleka by Bolton & Stegenga (1987), but the name is ‘uncertain’, as is the name Enteromorpha multiramosa Bliding (Guiry & Guiry, 2012).

Key to species

1a. Mature thallus tubular

2

1b. Mature thallus sheet-like

8

2a. Thallus unbranched

3

2b. Thallus branched

4

3a. Thallus thread-like; less than 50 µm in diameter

U. torta

3b. Thallus bladder-like; tubular to cuneiform

U. intestinalis

4a. Thallus sparsely branched near base; up to 10 mm tall; cup-shaped to peltate

U. tanneri

4b. Mature thallus at least several cm long

5

5a. Laterals arising near base of; and reaching same length as; main axis

U. flexuosa

5b. Most or all laterals shorter than main axis

6

6a. Axes profusely branched; many branches short and spine-like

U. clathrata

6b. Axes sparsely to profusely branched; spine-like branches absent

7

7a. Laterals mainly from proximal thallus; in section cells 12-17 µm high; square to slightly higher than broad

U. prolifera

7b. Laterals also from mid and distal parts of thallus; in section cells 15-30 µm high; 2-4 x higher than broad

U. compressa

8a. Thallus sheet-like; distromatic; blades broadly ligulate; margins with double dentation

U. rhacodes

8b. Thallus sheet-like; distromatic; double dentation absent

9

9a. Thallus deeply incised; forming several narrow (1-3 cm wide) ribbon-like blades

U. fasciata

9b. Thallus ovate to irregulary shaped; entire or variously incised

10

10a. Thallus stiff especially near base; basal margins with minute teeth; blade ca. 75 µm thick near apex

U. rigida

10b. Thallus up to a few cm tall; rosette-like; blade 35-40 µm thick near apex

U. uncialis

Order Ulvales

Family Ulvaceae

Ulva clathrata (Roth) C.Agardh 1811: 23

Plants light to dark green, tubular, highly branched, 10-40 cm long and 100 µm to several mm wide, usually with many spiny multiseriate branchlets; attached or in mats. Cells in longitudinal rows, rectangular with rounded corners, in surface view 15-20 µm. Chloroplast discoid in surface view, flattened in side view, containing several pyrenoids.

Collections, ecology and regional distribution

Collected in Knysna Lagoon and Mtakatye Estuary (near Hluleka) (30-45); probably more widespread.

World distribution: reportedly widespread in temperate and tropical waters (Guiry & Guiry 2012).

Notes:

1. Cells in our material somewhat smaller than reported for plants from Britain and Ireland (Maggs et al. in Brodie et al., 2007)

2. Our specimens were originally recorded as Enteromorpha ramulosa (Smith) Carmichael, now considered to be a synonym of Ulva clathrata.

Ulva clathrata, fresh material, Mtakatye Estuary near Hluleka, Transkei

Ulva clathrata, surface detail of fresh material, showing spiny branchlets, Mtakatye Estuary near Hluleka, Transkei

Order Ulvales

Family Ulvaceae

Ulva compressa Linnaeus 1753: 1163

Plats grass green to dark green, with a tubular or (usually apically) compressed main axis, up to ca. 20 cm long, narrow below, gradually expanding upwards to a maximum width of 10 mm, sometimes with a few constrictions. Laterals narrower than main axis, in part filiform, inserted on the lower half of the main axis but often reaching the same length. Cells in surface view in no definite arrangement, rounded, 5-10 µm in diameter, with a chloroplast located against the distal radial cell wall, with one pyrenoid. Thallus membrane (one cell layer) varying in thickness from 20 µm in young proliferations to 40 µm in the main axis: cells 15-30 µm high, 2-4 times longer than broad. Rhizoidal cells darker and slightly larger than normal vegetative cells; in the upper basal part the two cell types mixed. (Description from Stegenga et al. 1997).

Collections, ecology and regional distribution

Recorded from False Bay to Durban (17-52). Found in upper eulittoral and supralittoral rock pools.

World distribution: virtually cosmopolitan (Guiry & Guiry, 2012).

Type locality: Probably Bognor, Sussex, England (Hayden et al. 2003: 289)

Note: previously known as Enteromropha compressa (l.) Greville.

Ulva compressa, Glencairn, False Bay

Ulva compressa, from Glencairn, False Bay

Ulva compressa, surface view of cells (Glencairn, False Bay specimen)

Ulva compressa, XS to show cell shape & size (Glencairn, False Bay, fresh material)

Ulva compressa. 1, Habit. 2, Surface view showing cell arrangement. 3, Cross section. Reproduced from Stegenga et al. 1997.

Order Ulvales

Family Ulvaceae

Ulva fasciata Delile 1813: 297 [pl. 58: fig. 5, 1826]

Plants grass green, up to 15(-30) cm tall, rather tough, divided into strap-like blades; blades often undulated and contorted with ruffled edges, 1-3 cm wide, gradually narrowing towards apices. Cells in surface view rounded rectangular to polygonal, unordered., 10-20 µm in diameter in mid-thallus. Lamina distromatic, ca 150 µm thick in mid thallus. Cells in cross section markedly higher than broad (25-35 µm high, 12-18 µm broad in mid-thallus near margins, up to 50 µm high in central mid-thallus and basal region ). Chloroplast parietal, pyrenoids 1-2 (14) per cell. Rhizoidal cells darker and larger than normal vegetative cells.

Collections, ecology and regional distribution

Recorded from False Bay to northern Kwazulu-Natal (17-58). Found in the eulittoral zone, usually in rock pools.

World distribution: widespread in tropical and temperate regions (Guiry & Guiry 2012)

Type locality: Alexandria, Egypt (Silva et al., 1996).

Note: although U. fasciata is reported to be a synonym of U. lactuca Linnaeus (O’Kelly et al., 2010) SA material of the former is genetically different to U. lactuca (L. Kandjengo, pers, comm..) and so we retain the name U. fasciata for our material.

Ulva fasciata showing typical blade shape

Ulva fasciata single blade

Ulva fasciata surface view of cells

Ulva fasciata, XS of blade showing cell shape

Ulva fasciata, longitudinal section through base of blade showing central rhizoidal cells

Ulva fasciata: 1, Habit. 2, Surface view of upper thallus. 3, Cross section of upper thallus. 4, Longitudinal section of thallus base. Drawings from Stegenga et al. 1997.

Order Ulvales

Family Ulvaceae

Ulva flexuosa Wulfen 1803: xxii, 1

Plants yellowish green, a few cm high. Main axis tubular in the proximal part and provided with many laterals reaching the same length as main axis; distal part of main axis and laterals narrow, ribbon-shaped, compressed and truncated. Cells in surface view in regular longitudinal rows, squarish or rectangular, 10-15 (-30) µm in largest diameter. Chloroplast situated against the outer peripheral cell wall, or against a radial wall but not consistently to one side, with 2 (-3) pyrenoids. Thallus membrane (1 cell layer) 15-20 µm thick; cells dome-shaped, 10-12 µm high, 0.5-1 times higher than broad. Rhizoidal cells elongate, up to 30 µm long in surface view (rhizoidal portion excluded), otherwise not different from normal vegetative cells; rhizoidal and other vegetative cells in general not mixed.

Description from Stegenga et al. (1997).

Collections, ecology and regional distribution

Recorded from False Bay to Mkambati (17-47). Found on wave-exposed supralittoral ledges as well as in estuaries.

World distribution: cosmopolitan (Guiry & Guiry, 2012).

Type locality: Italy, Adriatic Coast (Guiry & Guiry, 2012).

Note: the description above ‘covers only part of the variation usually recognized’ in Ulva flexuosa (Stegenga et al., 1997. This species was previously known as Enteromorpha flexuosa).

Ulva flexuosa BOL 147374 (Tsitisikamma, on Gigartina paxillata)

 Ulva flexuosa showing branching near base (stained slide material).

 Ulva flexuosa showing arrangement of cells in surface view

Ulva flexuosa. 1, Habit of small plant. 2, Surface view showing longitudinal cell rows. 3, Cross section of upper thallus. Drawings from Stegenga et al. 1997.

Order Ulvales

Family Ulvaceae

Ulva intestinalis Linnaeus 1753: 1163

Thallus grass green to dark green or yellowish green in sheltered pools or lagoons. Plants up to 50 cm tall, tubular or with compressed apical part, narrowly to broadly cuneate in outline, surface often wrinkled. In surface view cells in no definite order, rounded, 6-12 µm in diameter; chloroplast situated against the distal radial cell wall, with one pyrenoid. Thallus membrane (one cell layer) varying in thickness from 17 µm near the apex to 30 µm in upper basal region. Rhizoidal cells larger and darker than the normal vegetative cells, the two types of cells mixed in the upper basal region.

Collections, ecology and regional distribution

Common along the whole South African coast in the lower eulittoral and in supralittoral pools; also in lagoons and estuaries and even in freshwater bodies where it often indicates nutrient pollution.

World distribution: virtually cosmopolitan (Guiry & Guiry, 2012).

Type locality: Woolwich, London, England? (Hayden et al. 2003).

Note: Stegenga et al. (1997) report that west coast lower eulittoral specimens tend to be broadly cuneate, whereas those found in quieter water have the typical ‘intestine’ shape. This species was known as Enteromorpha intestinalis.

Ulva intestinalis Kini Bay near East London (BOL 147292).

Ulva intestinalis showing cells in surface view

Ulva intestinalis, XS showing single cell layer

Ulva intestinalis. 1, Habit. 2, Cross section of basal thallus. 3, Deatail of cross-sectional anatomy of basal thallus. 4, Surface view of basal part. 5, Cross section of upper thallus. 6. Surface view of upper thallus. 6. Surface view of upper thallus showing chloroplasts in vegetative cells and formation of sporangia.

Order Ulvales

Family Ulvaceae

Ulva prolifera O.F.M üller 1778: 7, pl. DCCLXIII: fig. 1

Plants light to grass green, up to 20 (-50) cm high; main axis obvious, narrow tubular below, gradually expanding upwards and tubular or compressed, usually not over 5 mm in diameter, branched to varying degrees. Laterals mainly arising from the proximal region of the main axis, thin, many filiform, others attaining the size of the main axis. Cells in surface view in regular longitudinal rows, angular, 7-15 µm in largest diameter, with a parietal chloroplast located against the outer peripheral wall, usually with one pyrenoid. Thallus membrane (one cell layer) 20-25 µm thick, but as thin as 12 µm in young proliferations. Cells 12-17 µm high, about as high as broad or slightly higher. Rhizoidal cells elongate, up to 25 µm long in surface view (excluding the rhizoidal part), otherwise not much different from normal vegetative cells, the two types in general not mixed.

Description from Stegenga et al. (1997).

Collections, ecology and regional distribution

Recorded along the whole coast of South Africa (1-58). Found in the eulittoral zone and in rock pools up to the subpralittoral as well as in lagoons.

World distribution: cosmopolitan (Guiry & Guiry, 2012).

Type locality: Lolland, Denmark (Guiry & Guiry, 2012).

Note: South coast plants appear to be generally smaller than those on the west coast.

Ulva prolifera, herbarium specimens from Kowie Lagoon

Ulva prolifera, stained microscope slide specimen showing fine filiform lateral branches

Ulva prolifera, re-hydrated herbarium specimens from Tsitsikamma showing XS (on left) and surface view (on right)

Ulva prolifera, stained slide specimen showing rows of surface cells

Ulva prolifera. 1, Habit (juvenile). 2, Base of plant. 3, Detail of upper thallus.

Order Ulvales

Family Ulvaceae

Ulva rhacodes (Holmes) Papenfuss 1960: 311, figs 7-9, pl. 6

Plants yellowish green, up to ca. 20 cm tall, varying in shape from narrowly linear-lanceolate to irregularly ovate with marginal lappets and a double dentation; consistently lax. Cells in surface view without much order, rounded angular, 8-16 µm in diameter, increasing to 25 µm in the basal region.Thickness of (distromatic) lamina from ca. 45 µm in the apical region to 80 µm in the mid-thallus and 120 µm in the upper basal region. Cell height 15-35 µm, 1-2 times higher than broad, much rounded on the outer periclinal wall. Chloroplast parietal, its position in the cell variable, generally with one pyrenoid but in the larger cells of the basal region often with 2 or 3 pyrenoids. Rhizoidal cells larger than the other vegetative cells; rhizoids not united in bundles.

Description from Stegenga et al., (1997).

Collections, ecology and regional distribution

Recorded from False Bay to Morgan Bay (17-43). Found in high intertidal pools; often epiphytic.

World distribution: also recorded from Namibia and Portugal (Guiry & Guiry 2012).

Type locality: Port Alfred, South Africa (Silva et al. 1996).

Ulva rhacodes, herbarium specimen from Namibia (BOL).

Ulva rhacodes, herbarium specimen showing small marginal teeth.

Ulva rhacodes, herbarium specimen showing surface view of cells (BOL).

Ulva rhacodes. 1, Habit of young plant. 2, Thallus margin in detail. 3, Surface view showing cell arrangement, 4, Section of middle thallus. 5, Longitudinal section of basal thallus.

Order Ulvales

Family Ulvaceae

Ulva rigida C.Agardh 1823: 410

Plants pale to grass green, up to 30 cm tall, irregularly incised or lobed, consistency firm, especially near the base; thallus margins near the base with minute teeth. Cells in surface view organized in long curved rows, rounded angular, 10-16 µm in diameter. Thickness of lamina from 75 µm in the apical region to 100 µm in the mid-thallus and increasing to 200 µm in the upper basal region. Cell height 25-35 µm , cells 2-4 times higher than broad, cylindrical with rounded angles at the outer periclinal wall. Chloroplast parietal, located against the outer periclinal cell wall or shifted to one of the radial cell walls; pyrenoids 1-3. Rhizoidal cells larger and darker than normal vegetative cells, in older plants forming ribs on the membrane surface.

Description from Stegenga et al. (1997).

Collections, ecology and regional distribution

Recorded from the Cape Peninsula to northern Kwazulu-Natal (16-58). Found from the shallow sublittoral to upper eulittoral.

World distribution: widespread in temperate and tropical seas, including East Africa (Guiry & Guiry 2012).

Type locality: Cadiz, Spain (Silva et al. 1996).

Note: Although Stegenga et al. (1997) considered this species to include South African records of U. uncialis (Kützing) Montagne, this is not supported by recent molecular evidence (L. Kandjengo, pers. comm.).

Ulva rigida, Arniston

Ulva rigida, herbarium specimens from a jetty in Knysna Lagoon

Ulva rigida, surface view of cells (cells each ca 15 µm in diameter)

Ulva rigida, XS showing cell shape and size

Ulva rigida. 1, Habit (fig, 2 typical of U. uncialis-like habit). 3, Surface view showing cell arrangement. 4, Longitudinal section of basal thallu. 5, Section of middle thallus. Drawings from Stegenga et al. 1997.

Order Ulvales

Family Ulvaceae

Ulva tanneri H.S.Hayden & J.R.Waaland in Hayden et al., 2003: 285

Plants yellowish-green, developing though stages from uniseriate filamentous to vesicular, finally opening apically to form a cup-shaped to peltate mature thallus, ca. 10 mm high, with lacerated thallus rim. Holdfast developing from rhizoidal extensions of many proximal cells; several erect thalli arising from a common holdfast. Thallus membrane at first (vesicular stage) monostromatic, becoming distromatic apically via periclinal division of the cells. Cells in surface view unordered or (especially basally) in roughly transverse rows. Cells 5-10 µm in diameter; chloroplast single, parietal, with one pyrenoid. Rhizoidal cells scattered throughout basal portion of the thallus, slightly larger and darker than normal vegetative cells. Thallus membrane in young vesicular plants 10-20 µm thick, cells about as high as broad; in mature thalli both monostromatic (lower) and distromatic (upper) parts reaching thickness of ca. 55 µm. Cells in basal part up to 20 µm high, 2-4 times as long as broad. Reproductive cells developing in the marginal parts of the mature thallus. (Description from Stegenga et al., 1997).

Collections, ecology and regional distribution

Recorded (as Chloropelta caespitosa) from a few localities on the west coast (Kalk Bay, Hangklip), as an epiphyte or in turfs (Stegenga et al. 1997), and from Three Sisters on the south coast.

World distribution: also known from Panama, Mexico, California, Hawaii, Japan, and Queensland (Guiry & Guiry April 2012).  

Type locality: San Pedro, California (Tanner 1980).

Note: formerly known as Chloropelta caespitosa Tanner, Stegenga et al. (1997) expressed some doubt that the South African material is the same as type material.

Ulva tanneri, slide material of whole thalli, BOL. Largest specimen ca 11 mm tall.

Ulva tanneri, slide material showing details of base and rhizoidal tuft (attachment)

Ulva tanneri, slide material showing descending rhizoids near base

Ulva tanneri. 1, Juvenile habit. 2, Mature habit. 3, Surface view, upper basal region. 4, Longitudinal section, upper basal region. 5, Section of distromatic thallus.

Order Ulvales

Family Ulvaceae

Ulva torta (Mertens) Trevisan 1841: 480

Plants green, filamentous, up to 50 cm long, thin, unbranched, (usually) unattached and occurring in strings or mats. Thallus comprising 3 -12 longitudinal rows of cells arranged in a tube surrounding a small central hollow. Thallus ca. 45 µm in diameter; cells square to rectangular, 12-28 µm in largest dimension. Chloroplasts parietal, usually with one pyrenoid.

Collections, ecology and regional distribution

Recorded from Table Bay to Mtakatye Estuary, Hluleka (on mangrove roots) (15-45). Found in protected localities such as harbours, lagoons and estuaries, usually entangled with other filamentous algae.

World distribution: widely distributed in temperate seas (Guiry & Guiry 2012).

Type locality: Frisian Islands, Germany (Silva et al., 1996).

Ulva torta, part of whole thalli (stained slide material, Hluleka, Transkei)

Ulva torta, detail of part of thallus (stained slide material, Hluleka, Transkei)

Order Ulvales

Family Ulvaceae

Ulva uncialis (Kützing) Montagne 1850: 248

Plants bright green, up to a few cm tall, irregularly lobed, with undulate margins. Thallus near apex ca. 35-40 µm thick, cells 1.5 as high as broad, with rounded corners. Thallus near base ca. 100 µm thick: cells rectangular, interspersed with rhizoidal cells; rhizoids extending between layers of cells to form thick interstitial layer.

Description based on Joska’s (1992) report on the lectotype specimen.

Collections, ecology and regional distribution

Recorded from Stilbaai to Mkambati (26-47). Found in the eulittoral zone and rock pools .

World distribution: Also recorded from Namibia, Mozambique, and Reunion (Guiry & Guiry 2012).

Type locality: ‘ad oras capenses’ (South Africa) (Silva et al. 1996).

Note: Stegenga et al. (1997) followed Joska (1992) in regarding this species as a small form of U. rigida. However, recent molecular work indicates that these South African entities are different (L. Kandjengo, pers. comm.).

Ulva uncialis, BOL 147727 small. These Woody Cape specimens are named U. rigida but annotated ‘uncialis form’ by H. Stegenga (see note above).

Ulva uncialis, XS of blade, specimen from Three Sisters (stained slide material).

Ulva uncialis, XS of basal part of specimen from Three Sisters (stained slide material). Note down-growing central rhizoidal cells.

Order Ulvales

Family Ulvellaceae

Thallus minute, comprising only prostrate filaments. Reproductive cells produced in barely modified vegetative cells.

Acrochaete sp.

Plants uniseriate, filamentous, prostrate, creeping in the cell walls of other algae. Filaments irregularly branched, cells ca. 10 µm long. Cells with parietal reticulate chloroplast. It is not clear whether this is the same Acrochaete sp. indet. described by Stegenga et al. (1997) from the west coast .

Collections, ecology and regional distribution

Endophytic in the cell walls of larger algae (e.g. Chaetomorpha aerea). Recorded from False Bay to Morgan Bay (17-43) but may be more widespread.

Acrochaete sp. on Chaetomorpha aerea (microscope slide EC 2119).

Acrochaete sp. on Chaetomorpha aerea (microscope slide EC 2119), general appearance.

Acrochaete sp as recorded on the South African west coast by Stegenga et al. (1997). It is not clear if this is the same species recorded on the south coast. 1-2, showing microscopic habit in cell walls of Bornetia repens and Anotrichium tenue, respectively, in fig. 2 with sporangia.

Order Cladophorales

Family Cladophoraceae

Chaetomorpha linum (O.F.M üller) Kützing 1845: 204

Plants bright to dark green, forming entangled masses of very long filaments; attachment structures absent. Filaments of uniform 250-300 µm diameter; cells cylindrical, 1-2 times as long as broad. Reproductive structures not seen.

Collections, ecology and regional distribution

Recorded from Table Bay harbour to northern Kwazulu-Natal (15-58). Found in sheltered environments such as harbours and estuaries.

World distribution: Virtually cosmopolitan in temperate and tropical seas (Guiry & Guiry 2012).

Type locality: Nakskov Fjord, Lolland, Denmark (Lipkin & Silva 2002).

Chaetomorpha linum, mat of filaments from upper reaches of the Goukou Estuary, Stilbaai

Chaetomorpha linum, detail of filaments, each 250-300 µm wide

Chaetomorpha linum. 1, Vegetative filament. 2, Chloroplasts with pyrenoids. Reproduced from Stegenga et al. (1997).

Order Cladophorales

Family Cladophoraceae

Chaetomorpha aerea (Dillwyn) Kützing 1849: 379

Plants erect, attached, comprising vivid green filaments up to 10 cm tall. Basal cell up to 1 mm long, with spreading lobed rhizoid; additional filaments originating from the rhizoid. Filaments cylindrical or slightly constricted at cross-walls, but cells becoming barrel-shaped in the distal (fertile) part of the filament. Cell diameter from 150-200 µm immediately above the basal cell to 200-300 µm in distal parts; cells 0.4-1.0 times as long as broad. Reproductive cells formed at apical ends of filaments, more or less barrel-shaped, about as long as broad. (Description from Stegenga et al. 1997).

Collections, ecology and regional distribution

Recorded from False Bay to northern Kwazulu-Natal (17-58). Found in the mid-high eulittoral or supralittoral rock pools, sometimes associated with sand cover.

World distribution: widespread in temperate and tropical seas (Guiry & Guiry 2012).

Type locality: Norfolk, England (Guiry & Guiry 2012).

Chaetomorpha aerea, Haga Haga

Chaetomorpha aerea, detail of cells

Chaetomorpha aerea, detail of basal cell and rhizoidal holdfast (slide preparation)

Chaetomorpha aerea. 1, Attachment. 2, Vegetative filament. 3, Fertile filament. Reproduced from Stegenga et al. (1997

Order Cladophorales

Family Cladophoraceae

Chaetomorpha antennina (Bory de Saint-Vincent) Kützing 1847: 166

Plants leaf-green to dark green, a few to 8 cm tall, in brush-like tufts, attached by stoloniferous rhizoids. Individual filaments straight, rather rigid, unbranched, septate. Basal cells characteristically elongated, up to 7.5 mm long, thick-walled, with annulations near base. Cells 400-750 µm in diameter, 700-1000 µm long, becoming broader to barrel-shaped distally. Distal cells often losing contents via spore release, becoming transparent.

Collections, ecology and regional distribution

Recorded from Hluleka to northern Kwazulu-Natal (45-58). Epilithic in the eulittoral and shallow sublittoral zones.

World distribution: widespread in the temperate and tropical Atlantic, Indian and Pacific Oceans (Guiry & Guiry 2012).

Type locality: Réunion (Silva et al. 1996).

Chaetomorpha antennina - empty cell walls where spores released

Order Cladophorales

Family Cladophoraceae

Chaetomorpha Kützing

Plants unbranched, filamentous, either erect and attached with an elongate basal cell or forming loose-lying clumps without basal cells. Cells rather thick-walled: chloroplasts parietal, reticulate, usually covering outer surface of protoplast, with several to many pyrenoids. Reproductive cells very similar to vegetative cells, in attached species forming at distal end of filament. Life history with two isomorphic phases. Sixty species are currently recognized, of which 6 are recorded from the South African south coast.

Key to the species

1a. Plants basally attached

2

1b. Plants forming loose clumps or mats or entangled with other algae

4

2a. Plants erect, basal cells very long (to 7.5 mm), annulated near base

C. antennina

2b. Plants erect, basal cell up to 4 mm long, without annulations

3

3a. Basal cell up to 4 mm long, thallus spirally coiled near base

C. spiralis

3b. Basal cell up to 1 mm long, thallus not coiled at the base

C. aerea

4a. Filaments stiff, more than 350 um in diameter, undulate (wavy)

C. vieillardii

4b. Filaments lax, less than 300 um in diameter

5

5a. Filaments about 100 um in diameter, cells 1-3 times as long as broad

C. natalensis

5b. Filaments 250-300 um in diameter, cells 1-2 times as long as broad

C. linum

Cladophorales

Cladophoraceae

Chaetomorpha natalensis (Hering) De Toni 1889: 275

Plants green to pale green, forming lax clumps, free-floating or entangled in other algae. Filaments fine; cells ca 100 µm in diameter, 1-3 times longer than broad. Reproductive structures not seen.

Collections, ecology and regional distribution

Recorded from Algoa Bay to the Durban (36-51). Found in upper tide pools and sheltered lagoon areas.

World distribution: Also recorded from Mauritius (Silva et al. 1996).

Type locality: Port Natal (Durban) South Africa (Hering 1841).

Chaetomorpha natalensis, Kowie Estuary, (slide EC37, identified as ‘cf natalensis’)

Cladophorales

Cladophoraceae

Chaetomorpha spiralis Okamura 1903: 131

Plants dark green, attached, forming entangled cylindrical filaments, stiff and coiled towards the base. Basal cell curved, thickening from ca 350 µm near rhizoidal attachment to ca 750 µm at distal end. Cells visible to the naked eye, 400-600 µm in diameter but often increasing to more than 1000 µm at the apex of the thallus, about as long as broad proximally but length/width ratio in some specimens increasing to up to 1:2 near apex. Reproductive structures not seen.

Collections, ecology and regional distribution

Recorded from Goukamma to Cape Vidal (29-56). Usually attached to and entangled with other seaweeds in the eulittoral zone.

World distribution: recorded from scattered localities in temperate and tropical seas (Guiry & Guiry 2012).

Type locality: Chiba Prefecture, Japan (Silva et al. 1996).

Note: Leliaert et al. (2001) first recorded this species from South Africa, and provide further information on local records.

Chaetomorpha spiralis, Double Mouth, attached to and entangled with Dichotomaria diessingiana

 Chaetomorpha spiralis, base of filament

 Chaetomorpha spiralis, detail of distal part of filament

Cladophorales

Cladophoraceae

Chaetomorpha vieillardii (Kützing ) M. J. Wynne 2011: 112, figs 1, 2 a, b

Plants leaf green to dark green forming unattached, loose tangled clumps of fairly tough, curled, stiffish, unbranched, septate filaments. Filaments 350-600 µm in diameter, cells visible to the naked eye, thick-walled, 1-1.5 x as long as broad.

Collections, ecology and regional distribution

Recorded from Port Alfred to northern Kwazulu-Natal (39-58). Found in the eulittoral zone and rock pools, often entangled with other algae. (But see Note 2 below).

World distribution: Widespread in warm temperate and tropical seas (Guiry & Guiry 2012).

Syntype localities: Trieste and Venice, Italy; England (Silva et al. 1996).

Note1: This species was previously known as Chaetomorpha crassa Kützing.

Note 2: There are several specimens in BOL (as C. crassa) but most appear to be coiled and cannot be clearly distinguished from C. spiralis. As a result we are uncertain as to whether this species occurs on the south coast. C. vieillardii is unattached, while C. spiralis is attached and narrows towards the base.

Chaetomorpha vieillardii (herbarium specimen, BOL)

Order Cladophorales

Family Cladophoraceae

Cladophora Kützing

Thalli uniseriate, filamentous, sparsely to profusely branched. Growth apical and /or intercalary. Cells multinucleate, chloroplasts parietal, either united in a network or discoid and densely packed. Life history with isomorphic generations: biflagellate gametes and quadrifalgellate zoospores produced in little-modified cells, usually terminal on branches.

Cladophora is a large, cosmopolitan genus with species occurring in marine, brackish and freshwater habitats. Morphological characters used to distinguish species include thallus organisation and branching patterns, and cell sizes. Because some of these characters are affected by environment, identification of species can be difficult. Some 182 species are currently recognised worldwide (Guiry & Guiry 2012), and we have records of 10 species from the South Coast, as well as a further 3 uncertain records (noted but not described here).

Uncertain records:

feredayi Harvey

Not recorded by Leliaert & Coppejans (2003) or Silva et al (1996) and our specimens (EC 439 East London , T 171 Hluleka) do not match Harvey’s type illustration (which shows a markedly fastigiate thallus) or the description and illustrations in Womersley (1984). One of our specimens is similar to Cladophora sp 1 indet of Leliaert & Coppejans (2003), but without more material, we cannot be sure.

Cladophora subsimplex Kützing

Our only tentative records for this species are microscope slides: one ‘cf’ from Three Sisters (near Port Alfred) and one from Tsitsikamma. It is not recorded by Leliaert & Coppejans (2003), or by Silva et al. (1996) for South Africa, or for Africa by Guiry & Guiry (2012, AlgaeBase). Without more material, we cannot confirm its occurrence on our coast.  

Cladophora afra Kützing

Note: This species, recorded from the ‘Mouth of Knysna River’ and described by Kützing , appears not to have been recorded or recognised since. Without illustrations, a more detailed description or examination of the type, it is not possible to relate it to some of the unidentified specimens available. Based on the information in Kützing (1849) and Barton (1893), Leliaert & Coppejans (2003; Table 1) note only that the habit is ‘free erect, flaccid filaments’, ‘filaments often curved’, ‘branching spreading, pseudodichotomous’ and the apical cells are 20-30 µm wide and basal cells 70-90 µm wide.

Key to species

1a.Thallus fan-like, branching in one plane from most cells of axes, neatly pinnate appearance, end branches distinctly tapering

C. ordinata

1b. Branching not as above

2

2a. Cells, at least in proximate parts of thallus, longer than 10 mm

3

2b. Cells shorter than 5 mm

4

3a. Proximal end of basal cell and proximal cells of main axes with annular constrictions

C. rugulosa

3b. Basal cells of erect axes much longer than cells above, proximal cells of erect axes usually thickened distally

C. radiosa

4a. Apical cells more than 90 µm in diameter

C. lehmanniana

4b. Apical cells less than 80 µm in diameter

5

5a. End branches of axes with short secund branchlets

C. sericea

5b. Branching not secund, or if secund branches present, branches not short

6

6a. Branching restricted to proximal parts of thallus

C. flagelliformis

6b. Branching not restricted to proximal parts of thallus

7

7a. Thalli forming mats of interwoven filaments with stoloniferous bases, uprights branched or unbranched

C. coelothrix

7b. Thalli forming tufts or cushions but without stoloniferous bases

8

8a. Apical cells tapering, young branchlets straight or almost straight

C. sp II

8b. Apical cells not tapering, young branchlets usually curved

9

9a. Plants forming dense flaccid tufts up to 5 cm tall, lateral usually shorter than main axes, 1-2 (-3) laterals per parent cell

C. albida

9b. Plants forming dark green cushions up to 5 mm tall, laterals frequently same length as main axes, usually a maximum of one branch per parent cell

C. sp I

Order Cladophorales

Family Cladophoraceae

Cladophora albida (Nees) Kützing 1843: 267

Plants medium green, forming dense flaccid tufts a few to ca 5 cm tall, irregularly and often unilaterally branched, attached by basal rhizoids. Growth acropetal but with intercalary divisions, new cell usually producing a lateral but sometimes several cells in a row unbranched. Laterals at acute to wide angles; 1-2 (-3) laterals per parent cell. Apical cells 10-50 µm in diameter and 1-20 times as long as broad; basal cells 20-80 µm in diameter and 1.5-8 times as long as broad.

Collections ecology and regional distribution

Recorded from De Hoop to Kenton-on-Sea (24-38). Found in intertidal pools and lower eulittoral.

World distribution: Widespread in temperate and seas, and previously recorded under many synonyms (Guiry & Guiry 2012).

Type locality: Island of Selsey, England (Womersley 1984).

Cladophora albida, habit (stained slide material )

Cladophora albida, branching detail (stained slide material )

 Cladophora albida, branch apices (stained slide material )

Order Cladophorales

Family Cladophoraceae

Cladophora coelothrix Kützing 1843: 272

Plants dark green, interwoven branched filaments forming mats; attached by rhizoids arising from basal, stoloniferous filaments. Upright branches arising from basal filaments. Growth mainly by division of conspicuous apical cell with intercalary divisions lower down the filaments. Upright filaments branched or unbranched; branched filaments with maximum of one lateral per cell, branching angle 20-50o, ultimate filaments and apical cells often curved. Apical cells cylindrical with rounded tips, 57-75 µm in diameter, 5-15 times as long as broad; prostrate cells cylindrical, 75-120 µm in diameter, 2.5-5 times as long as broad.

Description based on Leliaert and Coppejans (2003).

Collections ecology and regional distribution

Recorded from Hluleka (on the shore and on mangrove prop-roots in Mtakatye Estuary) to Sodwana Bay (45-57). Found in the eulitoral zone and down to at least 20 m depth (Leliaert and Coppejans 2003).

World distribution: Widespread in temperate and seas, and previously recorded under many synonyms (Guiry & Guiry 2012).

Type locality: Gulf of Genoa, Italy (Leliaert and Coppejans 2003).

Cladophora coelothrix, re-drwn from Leliaert & Coppejans (2003: Fig. 2)

Order Cladophorales

Family Cladophoraceae

Cladophora flagelliformis (Suhr) Kützing 1849: 388

Plants dark green, erect, up to about 10 (-20) cm tall, forming dense tufts, attached by matted rhizoids developing from basal cells of erect filaments. Percurrent main axis obvious in erect filaments, although not different in size from many primary laterals. Growth in main filaments intercalary, in young laterals also by apical cell division. Branching irregular, up to four laterals per cell in west coast plants but fewer (usually only one per cell) in east coast plants. Laterals cut off via an oblique wall that moves into a transverse position in older branches. Laterals rebranched, often with short ramuli on proximal parts, but in distal parts unbranched and flagelliform. Apical cells of growing branches cylindrical or slightly tapering, 50-80 µm in diameter, up to 400 µm long; main axis and primary laterals ca. 100-150 µm in diameter, increasing to ca. 400 µm in the fertile tips; cells 1-3 times longer than broad (up to 5 times proximally).

Note: The cell dimensions of west coast material (Stegenga et al. 1997) differ somewhat from east coast material, but the dimensions of the latter fall within the limits of the former (Leliaert & Coppejans 2003). Our south coast specimens are in general smaller than those from the west coast.

Collections ecology and regional distribution

Recorded along the west coast and as far east as Durban; in the lower eulitoral zone and rock pools (1-52).

World distribution: Also recorded from Auckland Islands, Namibia, Tristan Da Cunha and Tanzania (Guiry & Guiry 2012).

Type locality: Cape of Good Hope (Silva et al. 1996).

Cladophora flagelliformis (habit)

Cladophora flagelliformis, individual thallus, ca. 3 cm long

 Cladophora flagelliformis, apical cells

Cladophora flagelliformis, branching

Cladophora flagelliformis, drawing reproduced from Stegenga et al. (1997).

Order Cladophorales

Family Cladophoraceae

Cladophora lehmanniana (Lindenberg) Kützing 1843: 268

Plants green, single or clustered in tufts, epilithic or epiphytic. Pseudodichotomous filaments arising from base of rhizoids, profusely branched from almost all distal cells, tapering slightly, often with unilaterally arranged branchlets; laterals usually at angle of 45o or more. Growth apical and intercalary. Apical cells 90-160 µm in diameter, 2-10 times as long as broad, apices rounded; cells of mid thallus 90-330 µm in diameter, 2-10 times as long as broad.

Description based on Womersley (1984) and Leliaert & Coppejans (2003).

Collections ecology and regional distribution

Recorded from Cape Agulhas and the south coast by Barton (1893: 55), and we have one record from Kini Bay, near East London (22-41). Reported to occur in intertidal and subtidal shaded habitats (Leliaert & Coppejans 2003).

World distribution

Also recorded from numerous warm temperate and tropical localities (Guiry & Guiry 2012).

Type locality: Helgoland, Germany (van den Hoek 1963).

Note: This species was recorded from South Africa by Barton (1893:55) as C. spinulosa and C. nuda (Leliaert & Coppejans 2003).

Cladophora lehmanniana, whole thallus, stained slide

Cladophora lehmanniana, detail of branch apices

Order Cladophorales

Family Cladophoraceae

Cladophora radiosa (Suhr) Kützing 1889: 354

Plants dark green, erect, a few to up to 40 cm tall, comprising numerous erect axes arising from a base of entangled branching rhizoids. Thallus organization acropetal, intercalary cell divisions rare, laterals cut off (usually from the subapical cell) via an oblique wall that in older parts of the thallus moves into a transverse position. Usually not more than two laterals per cell. Terminal branch systems often standing out as rather separate from lower axes as older cells elongate. Apical cells 150-200 µm in diameter, about 4-8 times as long as broad, cylindrical with rounded apices. Proximal cells of erect axes up to 600 µm in diameter and 15 (-40) mm long, cylindrical or slightly dilated at distal end. In fertile plants terminal branches becoming elongate, unbranched, with relatively short cells.

Description from Stegenga et al. (1997).

Collections ecology and regional distribution

Recorded from Table Bay eastward to Durban (15-51). Epilithic in the lower eulittoral and sublittoral; intertidal and sublittoral fringe plants are usually shorter (to about 15 cm). Smaller plants can form rather bushy tufts or turfs.

World distribution: Also recorded from Gough Island (South Atlantic) and India (Guiry & Guiry 2012).

Type locality: Algoa Bay, Cape Province, South Africa (Silva et al. 1996).

Cladophora radiosa, Arniston.

Cladophora radiosa, detail of distal branching (scale divisions 1 mm).

Cladophora radiosa, detail of elongated basal cell (scale divisions 1 mm).

Cladophora radiosa, . 1, Habit. 2, Detail of thallus apex. Drawing reproduced from Stegenga et al. (1997).

Order Cladophorales

Family Cladophoraceae

Cladophora rugulosa G. Martens 1866: 112, pl. II: fig. 3

Plants dark green, erect, 3-20 (-30) cm tall, comprising stiff tufts formed by numerous densely clustered stipes bearing pseudodichotomously to oppositely branched main axes with dense terminal branches. Attached by rhizoids from base of stipe. Stipe of single club-shaped cell with annular basal constrictions. Cells of terminal branch systems bearing one or two laterals, further from apices up to five laterals may be produced. Cells in basipetal direction longer and increasingly club-shaped with annular constrictions at the base. Proximal ends of old cells often bearing rhizoid-like protruberances that attach to parent cell below. Apical cells tapered, 130-260 µm in diameter, cells of main axes up to 550 µm in diameter and 18 mm long. Cell walls of main axes, basal cells and stipe up to 130 µm thick.

Description largely from Coppejans et al. (2005).

Collections ecology and regional distribution

Recorded from Cannon Rocks to northern Kwazulu-Natal (38-58). Epilithic in the lower eulittoral/sublittoral fringe, usually in wave-exposed areas. The most common species in Kwazulu-Natal (Coppejans et al. 2005).

World distribution: Probably endemic to South Africa (Coppejans et al. 2005).

Type locality: Port Natal (Durban), South Africa (Coppejans et al. 2005).

Note: For a discussion of the relationship of this species to C. prolifera, see Coppejans et al. (2005).

Cladophora rugulosa, Haga Haga

Cladophora rugulosa , middle of thalli.

Cladophora rugulosa , distal branches.

Cladophora rugulosa , detail of annulations at bases of branches.

Order Cladophorales

Family Cladophoraceae

Cladophora sericea (Hudson) Kützing 1843: 264

Plants pale to grass-green, erect, up to ca. 10 (-20) cm tall, attached by rhizoids. Growth mainly scattered intercalary; branching of terminal systems acropetal to irregular, apical branch systems often of main axis with long secund series of short branchlets. Main axis pseudodichotomously branched. Laterals cut off via an oblique cross wall that moves into a transverse position in older branches. Branch angle of laterals off main axis 30-45o, up to 3 laterals per cell. Apical cells tapered with blunt tip, 15-70 µm in diameter, cells of main axes up to 50-170 µm in diameter, 2-10 times longer than broad.

 Description from Stegenga et al. (1997) and Leliaert & Coppejans (2003).

Collections ecology and regional distribution

Recorded from Melkbosstrand on the west coast to De Hoop (15-24) (Stegenga et al. 1997). Found in the eulittoral zone and rock pools, also able to grow in low salinity water (Leliaert & Coppejans, 2003).

World distribution: Virtually worldwide in temperate and tropical waters (Guiry & Guiry 2012).

Type locality: Kent, England (Leliaert & Coppejans 2003).

Cladophora sericea, Arniston

Cladophora sericea, Arniston (scale divisions 1 mm)

Cladophora sericea

Cladophora sericea, thallus apex. Drawing reproduced from Stegenga et al. (1997).

Order Cladophorales

Family Cladophoraceae

Cladophora sp. I indet (see Stegenga et al. 1997: 111, Plate 21:4)

‘Plants forming minute dark green cushions 1-5 (-15) mm high and of about the same diameter. Thalli consisting of dense bundles of branched filaments, the basal part more or less endophytic in crustose algae. Organisation of the thallus feebly acropetal, both apical and intercalary cell divisions occurring: thallus apices often strongly curved. Branching virtually subdichotomous, laterals frequently reaching the same length as main axes. Laterals cut off via an almost transverse septum. Remaining appressed against the main axis; usually not more than one branch per cell. . Apical cells 30-45 µm in diameter, cylindrical with rounded apex. Main axes 40-65 µm in diameter, cell length from 1-3 times the diameter in distal portions to 4-6 (-15) times in proximal portions. Fertile cells developing in terminal branch sections, swollen, up to 70 µm in diameter, little longer than broad’. (Description from Stegenga et al. 1997).

Collections ecology and regional distribution

Recorded from False Bay to Goukamma oyster beds (17-29). ‘Often semi-endophytic on crustose algae, both fleshy (Ralfsia) and calcareous (Corallinaceae), also on the reef worm Gunnarea: in the intertidal almost up to high water mark’: Stegenga et al. (1997).

World distribution: Unknown

Cladophora sp. I thallus shape

Cladophora sp. I. Detail of thallus shape.

Cladophora sp. I. Detail of thallus apices.

Cladophora sp. I. Detail of proximal axes and laterals.

Cladophora sp. I. Microscopic habit, some thallus apices fertile. Drawing reproduced from Stegenga et al. (1997).

Order Cladophorales

Family Cladophoraceae

Cladophora sp. II indet

Plants up to 5 mm tall, attached by branched multicellular rhizoids arising from basal cell. Branching acropetal, branches arising 4-6 cells below apical cell, below this almost all cells producing branches, at angles of 20-40o. Branches usually one per cell, cells of main axes rarely with additional branches, some lateral on parent cell. Apical cells 25-30 µm in diameter , 3-6 times as long as broad, apices blunt. Cells in mid-lower axes 40-50 µm in diameter , 3-8 times as long as broad

Collections ecology and regional distribution

Recorded from Port Elizabeth and Kini Bay near East London (36-41). Found in the mid-lower eulittoral zone.

World distribution: Unknown

Note: this entity does not fit the description of Cladophora sp indet of Leliaert & Coppejans (2003), which has larger cells.

Cladophora sp II (stained slide EC 153)

Cladophora sp II, mid-upper thallus showing branching details

Cladophora sp II, apices

Order Cladophorales

Family Cladophoraceae

Rhizoclonium riparium (Roth) Harvey 1849: pl. CCXXXVIII

Plants yellowish to dark green, filaments unbranched or with lateral rhizoids; rhizoids continuous with normal vegetative cells, only occasionally developing into a multicellular structure. Growth via intercalary cell division. Cells cylindrical, 20-35 µm in diameter. (0.5-) 1-2 (-5) times as long as broad. Chloroplast parietal, reticulate, with few to several pyrenoids.

Collections, ecology and regional distribution

Recorded from Langebaan Lagoon to the Cape Vidal Area (13-56). Found in the upper eulittoral, on shaded rock walls, often entangled with Bostrychia; also recorded from estuaries, where it forms loose mats or grows attached to floating structures (e.g. Knysna Lagoon).

World distribution: Cosmopolitan, in marine, brackish and some freshwater habitats (Guiry & Guiry 2012).

Type locality: East Frisian Islands, Germany (Silva, et al., 1996).

Note: the distinction between this genus and Chaetomorpha is uncertain, and appears to be based mainly on the larger diameter of the latter (see Stegenga et al. 1997).  

Rhizoclonium riparium, filaments embedded in sand, Goukamma oyster beds (habit, herbarium sheet).

Rhizoclonium riparium, filaments embedded in sand, Goukamma oyster beds (habit, herbarium sheet).

Rhizoclonium riparium, Knysna estuary.

Rhizoclonium riparium, detail of cells.

Rhizoclonium riparium, filament with lateral rhizoid.

Rhizoclonium riparium, 1-5: details of filaments in various stages of development. Drawings reproduced from Stegenga et al. (1997).

Order Cladophorales

Family Cladophoraceae

Willeella ordinata (Børgesen) C.Hoek 1982: 123, pl. 22: figs 235-237

Plants green to dark green, 4-8 cm tall, comprising bushy tufts with distinct main axes; attached by rhizoids from basal cell. Growth apical and intercalary. Cells thinner but much longer towards bases of axes. Branching in one plane, from distal ends of cells, opposite in distal regions, with some flabellate branching lower down. Terminal branches distinctly tapering. Angle of branching between laterals and main axis 35-45o in opposite branches, 20-65o in flabellate branches. Apical cells conical with blunt tip and thickening of cell wall at apex, 30-45 µm in diameter, 2-3.5 times as long as broad; cells of terminal branches 45-120 µm in diameter, 1-3 times as long as broad.

Description based on Leliaert & Coppejans (2003).

Collections ecology and regional distribution

Recorded from Mkambati to Mabibi (north of Sodwana Bay in Kwazulu-Natal) (47-57). Epilithic, from intertidal rock pools to 37m depth (Leliaert & Coppejans 2003).

World distribution: A 'disjunct distribution pattern in the tropical to warm-temperate Atlantic and Indo-Pacific' regions (Leliaert & Coppejans 2003).

Type locality: India (Leliaert & Coppejans 2003).

Note: this species was previously called Cladophora ordinata, but the genus Willeella was resurrected by Boedeker et al. (2016). For further details and illustrations of South African material see Leliaert & Coppejans (2003).

Willeella ordinata, Palm Beach, KZN

Willeella ordinata, detail of cells and branching.

Order  Siphonocladales

Family  Siphonocladaceae

Chamaedoris Montagne

Thallus broom-like, with unbranched stipe bearing a capitulum. Capitulum structure of closely adherent and entangled siphons; siphons branched, septate. Cells multinucleate, with many discoid chloroplasts, each with a single pyrenoid. Life history biphasic, isomorphic. There are three species, of which two occur on our south coast. For further details of the genus and its relationship with other genera, see Leliaert et al. (2007).  

Key to the species

1a. Capitulum (usually) penicillate, becoming ball-shaped when older, apical cells of capitulum filaments 70-200 µm in diameter

C. delphinii

1b. Capitulum (usually) flattened, becoming auriculate to peltate when older; apical cells of capitulum filaments 50-140 µm in diameter

C. auriculata

Order Siphonocladales

Family Siphonocladaceae

Chamaedoris delphinii (Hariot) Feldmann & Børgesen in Børgesen 1940: 16-20, 21, footnote, fig. 5, pl. I

Plants dark green, erect, brush-like, 3-8 cm tall, often in groups. A single-celled stipe with annular constrictions bears a flat, auriculate (ear- or fan-shaped) capitulum made up of many adherent filaments; basal capitulum cells 120-250 µm in diameter, apical capitulum cells (45-) 60-110 (-140) µm in diameter.. Structure similar to C. delphinii, but see Leliaert et al. (2007) for details.

Collections, ecology and regional distribution

Recorded from Mzamba to northern Kwazulu-Natal (48-58). Found in the lower eulittoral zone and sublittoral down to at least 18m (Leliaert et al. 2007).

World distribution: Also recorded from Mozambique to Somalia, Yemen, India and Australia and there is one confirmed Pacific record from the Coral Sea (Leliaert et al. 2007).

Type locality: Gujarat, India (Leliaert et al. 2007).

Chamaedoris auriculata showing flattened capitulum (head).

Order  Siphonocladales

Family  Siphonocladaceae

Chamaedoris delphinii (Hariot) Feldmann & Børgesen in Børgesen 1940: 16-20, 21, footnote, fig. 5, pl. I

Plants dark green, erect, brush-like, 4-8 cm tall, often in groups. Stipe of single cell, attached by rhizoids from basal end, with annular constrictions along whole length, usually covered with encrusting coralline algae. Capitula brush shaped, becoming globose when older, very rarely flattened; comprising branched entangled filaments: basal capitulum cells 160-400 µm in diameter, apical capitulum cells 70-200 µm in diameter.. Stipe cell 2-7 cm long, 400-950 µm in diameter at base, widening to 1300-1650 µm at apex; cell walls markedly stratified.  

For further details on South African specimens see Coppejans et al. (2005).

Collections, ecology and regional distribution

Recorded from the Port Alfred area to northern Kwazulu-Natal (39-58). Found in mid-lower eulittoral zones and subtidally to at least 15 m, usually in fairly exposed localities.

World distribution: Also found in Madagascar, Mauritius, and the east coast of Africa from Mozambique to Somalia. (Guiry & Guiry 2012). However, Leliaert et al. (2007) note that the records from Kenya, Tanzania and Somalia may be referrable to C. auriculata.

Type locality: Fort Dauphin, Madagascar (Silva, et al., 1996).

Note: According to Leliaert et al. (2007) this species can become auriculate, making it difficult to distinguish from C. auriculata, and these two species are best distinguished by the size of cells of the capitulum.

Chamaedoris delphinii, upper stipes covered with encrusting coralline alga.

Order Siphonocladales

Family Valoniaceae

Valonia C. Agardh

Thallus of large, siphonous, subclavate to elongate cells forming cushions of indeterminate size; lacking stipes. Branching from lenticular cells, cross-walls only at branching points. Attachment by basal cells, well-developed rhizoidal system lacking. Cells multinucleate, with many discoid chloroplasts per cell, each with one pyrenoid. Members of this genus widely distributed in the tropics. Ten species currently recognized (Guiry & Guiry, 2012), of which two are found on the south coast.

Key to species

1a. Diameter of cells 1-3 mm

V. aegagropila

1b. Diameter of cells more than 3 mm (up to 35 mm)

V. macrophysa

Order Siphonocladales

Family Valoniaceae

Valonia aegagropila C.Agardh 1823: 429-430

Plants light green, comprising cushions up to 10 cm or more in diameter, of tightly-packed bladder-like cells. Cells 1-3 mm in diameter, up to 20 mm long, straight or clavate; branching from swollen distal ends of parent cells or rarely lateral on parent cell.

Collections, ecology and regional distribution

Recorded from East London to northern Kwazulu-Natal (41-58). Found in the sublittoral fringe and shallow sublittoral zone.

World distribution: cosmopolitan in tropical regions (Guiry & Guiry 2012).

Type locality: Venice, Italy (Silva et al. 1996).

Valonia aegagropila, Presley Bay (fingertips for scale)

Order Siphonocladales

Family Valoniaceae

Valonia macrophysa Kützing 1843: 307

Plants dark green, comprising cushions of large, bladder-like cells. Cells 3-35 mm in diameter, each with 1-8 terminal or lateral branches. Cushions from a few to more than 20 cm in diameter. Attachment by minute rhizoids arising from basal cells.

Collections, ecology and regional distribution

Recorded from Morgan Bay to northern Kwazulu-Natal (44-58). Found on vertical or overhanging rock from tide pools down to more than 20 m depth.  

World distribution: widespread in tropical and warm temperate waters (Guiry & Guiry 2012).

Type locality: Lessina, Croatia (Kützing 1843).

Valonia macrophysa, Mzamba.

Order Bryopsidales

Family Bryopsidaceae

Genus Bryopsis J. V. Lamouroux

Thallus of gametophyte (conspicuous phase) of coenocytic filaments (siphons) forming turfs, tufts, or individual bushy plants from a few to 10 (-15) cm high. Individual thalli of erect uniaxial siphons, usually with small branches (ramuli) and rhizoidal holdfasts. Sexual reproduction involves formation of anisogametes in little-modified branches that are shed after release.

Life histories comprise alternation of generations. In one type, zygotes produce a sporophyte that is a creeping microthallus which produces zoospores. In another, zygotes develop directly into the characteristic macrothallus: the latter has been shown in culture for B. flanaganii (now included in B. myosuroides) from South Africa (Harper & Pienaar 1985).

The taxonomy of Bryopsis is problematic because molecular studies have shown that morphological characters appear to be unreliable in distinguishing between species (Krellwitz et al. 2001). In the absence of definitive studies, we provisionally accept six species on the south coast, based on morphological characters of the gametophytes.

Key to Bryopsis on south coast

1 a Short (up to 1 cm) compact turf of mainly unbranched siphons

B. pusilla

1 b Turf or bushy clumps of mainly branched siphons

2

2 a Main axes about 125 µm in diameter, plants very fine

B. caespitosa

2 b Main axes 150 µm or more in diameter

3

3 a Plants densely caespitose, often sand-binding, main axes usually with unbranched ramuli

B. africana

3 b Plants fairly open in habit; erect axes with 2-3 orders of branches

4

4 a Branching mainly polystichous (sometimes pinnate near apices); apices narrowly pyramidal in shape

B. hypnoides

4 b Branching distichous

5

5 a Main axes 300-450 um in diameter; ramuli angled upwards and curving inwards, featherlike appearance

B. myosuroides

5 b Main axes up to 600 um in diameter; ramuli decreasing in length towards apex of axis creating a narrowly pyramidal outline

B. plumosa

Order Bryopsidales

Family Bryopsidaceae

Bryopsis africana Areschoug 1851: 5

Plants dark green, caespitose, forming clumps several cm wide and up to 5 cm high. Individual axes up to 300 (-400) um wide narrowing slightly towards apex. Axes unbranched or branched, branching irregular, branches various lengths, polystichously arranged or often secundly arranged in short rows; branches seldom of second order. Usually some branches long (up to 20 mm), reaching level of the apex of main axis and imparting candelabrum-like outline. Branches about 200 um wide; older branches producing descending rhizoids that impart felty texture to the plant.

Collections, ecology and regional distribution

Along the whole west coast and on the south coast as far as Kei Mouth (1-43). Found throughout the eulittoral zone, often as a sand-binding turf.

Syntype localities: False Bay and Saldanha Bay (Silva et al. 1996).

Note: We follow Stegenga et al. (1997) in including B. tenuis Levring in B. africana.

Bryopsis africana, exposed at low tide, Arniston

Bryopsis africana, detail of apical branches

Bryopsis africana, apices of erect filaments (reproduced from Stegenga et al. 1997).

Order Bryopsidales

Family Bryopsidaceae

Bryopsis caespitosa Suhr ex Kützing 1849: 490

Plants caespitose, medium to dark green, forming bushy clumps a few cm high. Main axis about 125 um diameter, narrowing gradually towards apex. Branching distichous, irregular, more distal branches reaching the level of the apex and imparting candelabrum-like outline.

Branches about 50-60 um diameter.

Collections, ecology and regionals distribution

South African endemic, collected from De Hoop to Durban KZN (24-51), in the lower eulittoral zone.

World distribution: Also recorded from Namibia, Japan, Korea and some Pacific islands (M. Guiry in Guiry & Guiry, 2014).

Type locality: ‘Kaffernkuste’, South Africa (Silva et al. 1996).

Note: Stegenga et al. (1996) point out that this species may be synonymous with B. africana, although the latter has thicker axes. However, the illustration of B. caespitosa in Kützing (1856) shows distichous branching, whereas branching in B. africana is polystichous.

Bryopsis caespitosa, irregular branches reaching level of main axes

Bryopsis caespitosa, chloroplasts

Order Bryopsidales

Family Bryopsidaceae

Bryopsis hypnoides Lamouroux 1809: 135

Plants light to dark green, bushy, up to 6 cm tall. Axes with up to 3 orders of branches, polystichously arranged but sometimes pinnate near the apices, apices shaped like narrow pyramid. Main siphons 400 (-500) µm in diameter, tapering towards end. Ramuli unbranched for up to 2.5 mm before branching, up to 150 µm diameter.

Collections, ecology and regional distribution

Collected from False Bay to Kei Mouth (17-43), in the lower eulittoral zone and in rock pools.

World distribution: Also recorded from Namibia (Rull Lluch 2002), Tanzania, Madagascar, Mauritius, Kenya (Silva et al. 1996). Distribution apparently almost worldwide.

Type locality: Mediterranean coast of France (Silva et al. 1996). 

Note: Some authors consider this species to be a growth form of B. plumosa.

Bryopsis hypnoides, Kei Mouth

 Bryopsis hypnoides, branching pattern

 Bryopsis hypnoides, note pyramidal branch tufts

 Bryopsis hypnoides, thallus apices (reproduced from Stegenga et al. 1997).

Order Bryopsidales

Family Bryopsidaceae

Bryopsis myosuroides Kützing 1856: 27

Plants medium-dark green, sometimes with bluish iridescence, forming dense tufts up to 8 cm tall; main siphons 300-450 µm diameter, with lateral branchlets along the apical 2-15 mm; branchlets 90-150 µm wide, distichously arranged, directed upward and curving inwards imparting distinctly feather-like appearance

Distribution and collections

Collected from Plettenberg Bay area to northern KZN (31-58). Common in rock pools and some shallow subtidal gulleys. Plants from intertidal pools tend to be longer and laxer than those from the intertidal shore.

World distribution: Also reported from Madagascar and various rather disjunct, mainly warm-temperate localities around the world (Silva et al. 1996).

Type locality: Durban, South Africa.

Note: this species includes the synonyms B. setacea and B. flanaganii. Coppejans et al. (2005) point out that B. myosuroides resembles the widespread tropical B. pennata, but they maintain the use of the former name for the South African taxon.

Bryopsis myosuroides, Haga Haga

 Bryopsis myosuroides, typical arrangement of branches

Order Bryopsidales

Family Bryopsidaceae

Bryopsis plumosa (Hudson) C. Agardh 1823: 448

Plants dark green, bushy, up to 10 cm tall. Siphons branched 1-3 times, pinnately; branchlets strictly distichously arranged, decreasing in length towards the apex to produce narrow pyramidal outline near the apex. Main siphon up to 600 µm diameter, tapering distally; branchlets about 100 µm diameter, unbranched for up to 5 mm before branching. 

Distribution and collections

In South Africa found from Table Bay harbour to northern KZN (17-58), in the lower eulittoral zone and rock pools. Long (12 cm), lax specimens were collected from floats in the protected environment of Table Bay harbor (Stegenga et al. 1997).

Worldwide distribution: widespread in in cool and temperate seas (Guiry & Guiry 2014).

Type locality: Devon, England. 

bryopsis
Bryopsis plumosa, herbarium specimen (scale numbers in cm)

bryopsis
 Bryopsis plumosa (scale numbers in cm)

Order Bryopsidales

Family Bryopsidaceae

Bryopsis pusilla Levring 1938: 11-13

Plants green, forming dense turf up to about 1 cm tall ; entangled basal system of horizontal rhizoids giving rise to usually unbranched erect siphons 0.4 – 1 cm high and 250-400 um thick.; branching rare, distichous, branchlets up to 1.5 mm long, 90-160 um thick, all branchlets reaching beyond apex of main siphon to impart brush-like appearance.

Collections, ecology and regional distribution

Recorded from Port Elizabeth to northern KZN (36-58) but may be distributed further westward, as several specimens tentatively identified as B. pusilla have been collected from False Bay and Cape Agulhas (BOL). Found in the lower eulittoral, generally in sand-binding turfs. Levring (1938) records that it occurs in a short Corallina turf. 

Worldwide distribution: also found in Mozambique (Silva et al. 1996).

Type locality: Port Elizabeth, Eastern Cape (Silva et al. 1996).

Note: Levring (1938) distinguishes this from other Bryopsis species on the basis of its smallness and growth form with a well-developed and interwoven horizontal system of rhizoids.

Bryopsis pusilla, Arniston

Bryopsis pusilla, with some fine filaments of a Chaetomorpha sp.

Order Caulerpales

Thallus coenocytic but crossed by trabeculae, differentiated into a horizontal stolon attached by short rhizoidal outgrowths and upright assimilators (fronds). Numerous chloroplasts in lumen, parietal together with storage bodies (amyloplasts). Life-history diplontic.

Family Caulerpaceae Greville ex Kützing

Contains the single genus Caulerpa.

Genus Caulerpa Lamouroux

Thallus coenocytic, differentiated into horizontal stolons, colourless rhizoidal haptera, and upright photosynthetic assimilators (fronds) of various shapes. Thallus internally undifferentiated except for trabeculae - extensions of the cell wall that run across the lumen.

Caulerpa is a large genus, with about 84 species currently recognized (Guiry & Guiry 2014), mainly tropical in distribution. Some species produce a poison, caulerpicin, which deters certain grazers and may make them toxic to humans. The thalli heal wounds (e.g. caused by fish grazing) by secreting a polysaccharide plug into the opening.

The morphological variability of many Caulerpa species has led to the description of numerous forms and varieties. Molecular studies have reduced the numbers of sub-specific taxa: in this guide we have not distinguished sub-specific taxa. We recognize six species from the south coast, with more species appearing in the tropical waters of northern Kwazulu-Natal (Coppejans et al. 2005).

Key to the species

1a. Erect fronds (assimilators) pinnate and neatly feather-like

C. holmesiana

1b. Assimilators not feather-like

2

2a. Branching dichotomous, assimilators strap-shaped

3

2b. Branching radial or distichous, assimilators globose or pear-shaped

5

3a. Assimilators long (10-30 cm) and wide (3-6 mm)

C. filiformis

3b. Assimilators short (1-5 cm) and 1.5 - 3 mm wide

4

4a. Assimilators several times dichotomously branched

C. bartoniae

4b. Assimilators not several times dichotomously branched

C. brachypus

5a. Assimilators spherical, on radially-arranged branchlets

C. racemosa

5b. Assimilators pear-shaped, branchlets alternate or opposite

C. zeyheri

Order Caulerpales

Family Caulerpaceae

Caulerpa bartoniae G. Murray 1896: 177-178

Plants light to grass-green, 2-5 cm tall. Stolons smooth, cylindrical, bearing erect fronds up to 5 cm tall (usually shorter), with a short cylindrical stipe and narrow (1.5 – 2.5 mm) strap-like blades that are several times dichotomously branched; dichotomies with an angle of 30-60o.  

Collections, ecology and regional distribution

Recorded from False Bay (near Cape Point) to the East London area (18-41). Found in rock pools and the shallow subtidal to at least 6 m deep, often forming extensive stands or intermingled in mixed algal turfs.

World distribution: South African endemic.

Type locality: Eastern Cape, South Africa, between Kei and Great Fish River (Silva et al. 1996).

Caulerpa bartoniae

Caulerpa bartoniae, fronds ca 4 mm wide

 Caulerpa bartoniae, drawing reproduced from Stegenga et al. (1997).

Order Caulerpales

Family Caulerpaceae

Caulerpa brachypus Harvey 1860: 333

Plants light to medium green, up to 20 mm tall. Stolons thin (0.5 mm in dried material) bearing short stipes with one or two (dichotomously branched) thin fronds, each 10-15 (-20) mm long and 3-4 mm wide, ovate to strap-shaped, with rounded apices.

Collections, ecology and regional distribution

Uncommon on the south coast: collected from intertidal shores in Transkei, at 23 m off Stilbaai and a few metres deep at De Hoop, but probably more common northwards into Kwazulu-Natal (24-58), where it is found from the intertidal down to 40 m (Coppejans et al. 2005), as C. brachypus forma parvifolia).

World distribution: Widespread in the Indian and Pacific Ocean tropics.

Type locality: Tanegasima, Japan (Harvey 1860).

Note: Coppejans et al. (2005) distinguish forma parvifolia from the considerably longer forma brachypus (Coppejans et al. 2004). See Wynne et al. (2009) for comparisons with similar species of Caulerpa.

Caulerpa brachypus, De Hoop, 2m depth

Caulerpa brachypus, frond detail

Order Caulerpales

Family Caulerpaceae

Caulerpa filiformis (Suhr) K. Hering 1841: 91

Plants bright green, usually forming seagrass-like beds in sandy gulleys. Rhizoidal branches (haptera) 2-10 mm long and 5-10 mm apart anchor smooth, cylindrical stolons to the rock; basal part of assimilators cylindrical, pale, with annular constrictions, up to a few cm long; assimilators flat, strap-like, 1-3 times dichotomously branched, up to 20 cm or more long, 3-5 mm wide, margin sometimes wavy, tips rounded; blades usually with black dots.

Collections, ecology and regional distribution

Found from False Bay, through to northern Kwazulu-Natal, and abundant in the Eastern Cape (17-58). Characteristically growing in the lower eulittoral to shallow sublittoral on sand-covered rocks in monospecific stands, stolons and haptera often concealed by sand. This alga has a bitter taste and probably contains anti-grazer compounds.

World distribution: Disjunct- known from Mozambique, but also recorded from Peru and New South Wales, Australia. (Guiry & Guiry 2012).

Type locality: Algoa Bay (Silva et al. 1996).

Caulerpa filiformis (background and Caulerpa holmesiana (foreground), False Bay, 4m depth.

 Caulerpa filiformis,  Woody Cape intertidal pool.

Caulerpa filiformis, individual thallus showing stolon and uprights

 Caulerpa filiformis, drawing reproduced from Stegenga et al. (1997).

Order Caulerpales

Family Caulerpaceae

Caulerpa holmesiana G. Murray 1891: 208-210

Plants dark green, sometimes with slight bluish iridescence. Stolons long, cylindrical and with annular contrictions. Distinctive feather-shaped assimilators comprising a cylindrical axis with annular constrictions and opposite rows of curved, tapering ramuli. Ramuli up to 7mm long, 0.5 mm diameter, slightly constricted at the base and rounded or pointed at the tip.

Collections, ecology and regional distribution

Characteristically a south coast species, but found from Cape Point to the Kei Mouth Area (17-43).Sublittoral (seldom exposed at low tide), often covering large areas of rock in monospecific stands and accumulating sand.

World distribution: South African endemic.

Type locality: Algoa Bay (Silva et al. 1996).

Caulerpa holmesiana

Caulerpa holmesiana individual feather-like thalli showing annulated rachis

Caulerpa holmesiana drawing reproduced from Stegenga et al. (1997).

Order Caulerpales

Family Caulerpaceae

Caulerpa racemosa (Forsskål) J. Agardh 1873: 35-36

Plants bright light-green, often looking like cushions of small grapes. Creeping cylindrical stolons 1-2 mm in diameter are attached by root-like rhizoids and bear erect assimilators that divide once or twice and are covered with (sometimes dense) radially-arranged branchlets each comprising a short (2-3 mm) stalk ending in a spherical (bead-like) tip 2-4 mm in diameter. The variable shape of the branchlets and vesicles has led to the description of many varieties and forms of this species.

Collections, ecology and regional distribution

Recorded from Port Alfred through Kwazulu-Natal into the tropics (39-58). Here it is found in the lower eulittoral and rock pools, often interwoven into algal turfs.

World distribution: varieties and forms of this species occur throughout the tropics.

Type locality: Egypt (Silva et al. 1996).

Note: In Polynesia this species (in various forms) is eaten raw as a salad.

Caulerpa racemosa, Kei Mouth

Caulerpa racemosa, detail of assimilators

Order Caulerpales

Family Caulerpaceae

Caulerpa zeyheri Kützing 1857: 4, pl. 8: fig. III

Plants bright light-green, usually forming dense cushions up to several cm high. Stolons 0.5-1.0 mm in diameter, profusely branched, attached to substratum by short rhizoidal branches and bearing erect, often dense, assimilators on short (1-2 mm) usually unbranched cylindrical stalks. Dense alternate (sometimes opposite) branchlets have swollen, pear-shaped tips up to 1mm or more in diameter.

Collections, ecology and regional distribution

Recorded from Haga-Haga to Mozambique (Coppejans et al. 2005) (42-58).

Lower eulittoral and eulittoral fringe, often interwoven with other algae.

World distribution: restricted to the southern African coast.

Type locality: "Coast of southern Africa" (Silva et al. 1996).

Caulerpa zeyheri, Double Mouth

Caulerpa zeyheri, detail of assimilator arrangement

Order Bryopsidales

Family Codiaceae

Genus Codium Stackhouse

Thallus coenocytic, filamentous, filaments adhering to form variously-shaped spongy structures; holdfast a tuft of rhizoids. Anatomically comprising a medulla of usually colourless filaments and an outer layer of usually terminally-swollen filaments (utricles) containing chloroplasts. Cell-wall thickenings usually present at junction of utricles and internal filaments. Species delimited on external habit and size and shape of utricles, which may bear hairs or scars. Note that utricles from near the tips of thalli are smaller, and dimensions given here are based on samples from near the middle of thalli.

Gametangia arise laterally from utricles; after meiosis the contents divide into biflagellate gametes which are extruded through ruptures apices of gametangia. Male gametes smaller, with only one or two chloroplasts, female gametes larger with numerous chloroplasts. Species may be monoecious or dioecious.

The descriptions below are largely based on the monograph on South African Codium by Silva (1959), which remains the authoritative work on this genus in the region.

Key to Codiums of south coast

1 a Thallus prostrate

2

1 b Thallus erect

9

2 a Utricles clearly visible to naked eye| 1.5-2.5 mm in diameter| thallus globose and light green

C. megalophysum

2 b Utricles not clearly visible to naked eye and less than 1 mm diameter| thallus smooth or velvety| various shapes

3

3 a Thallus circular in outline| more than 10 mm thick| globose; utricles longer than 1.5 mm| 350-520 um diameter at apex

C. papenfussii

3 b Thallus with irregular outline

4

4 a Thallus dichotomously branched| mainly or entirely prostrate

C. prostratum

4 b Thallus not dichotomously branched

5

5 a Thallus strikingly membrane-like| 1.5–3 mm thick| loosely attached to substratum

C. pelliculare

5 b Thallus in mature parts usually thicker than 3 mm| applanate

6

6 a Thallus with well-developed more-or-less free lobes| utricles markedly ninepin-shaped

C. stephensiae

6 b Thallus attached on most of under-surface| utricles cylindrical or club-shaped

7

7 a Utricles mostly shorter than 1 mm| only edges of thallus free

C. lucasii subsp. capense

7 b Utricles mostly longer than 1 mm| thallus firmly attached to substratum over whole under surface

8

8 a Utricles without hairs| gametangia cylindrical to spindle-shaped

C. incognitum

8 b Utricles with abundant hairs| gametangia lanceolate-ovoid or flask-shaped

C. spongiosum

9 a Thallus flattened| up to several cm wide

C. platylobium

9 b Thallus completely cylindrical or largely cylindrical except sometimes for flattening at forkings

10

10 a Utricles markedly mucronate (pointed tips)

C. fragile subsp capense

10 b Utricles non-mucronate

11

11 a Branch forks of noticeably unequal length| giving thallu cervicorn appearance| branches uneven in width

C. pocockiae

11 b Branch forks of similar length| branches of even width but may narrow towards tips

12

12 a Thallus pale green| translucent at tips| markedly flattened at forkings

C. tenue

12 b Thallus dark green| not translucent at tips| terete or slightly compressed throughout

13

13a Utricles often longer than 1 mm

C. duthieae

13 b Utricles seldom as long as 1 mm

14

14 a Utricles capitate (milk-bottle shaped)| slender| with tiny pits

C. capitatum

14 b Utricles stout| cylindrical to club-shaped

15

15 a Utricles without hairs| thallus terete throughout| 3-6 mm diameter| not narrowing towards tips

C. isaacii

15 b Hairs or hair-scars common on utricles| thallus terete except for flattening near base| narrowing from 4-8 mm lower down to 1.5 - 2 mm near apices

C. extricatum

Order Bryopsidales

Family Codiaceae

Codium capitatum P.C.Silva 1959: 135-138

Thalli dark green, erect, dichotomously branched, cylindrical, up to 20 cm long, slender, smooth (no hairs), attached by weft of branched filaments. Erect branches uniform in diameter (2-3.5 mm) throughout. Utricles cylindrical, 350-700 µm long, 100-200 (250) µm in diameter, usually with distinct constriction below the rounded tip (i.e. capitate); cell wall thickened near end of utricle; hairs seldom present.

Collections, ecology and regional distribution

Found from about Port St Johns northward through KZN (46-58) (Silva 1959). Attached to rock in pools and shallow sublittoral.

World distribution: also recorded from Mozambique, Kenya and Madagascar (Guiry in Guiry & Guiry 2014).

Type locality: Umhlanga rocks, KZN (Silva et al. 1996).

Note: Although superficially similar to some other local Codium species, C. capitatum is distinguishable by its capitate utricles.

Codium capitatum, general habit

Codium capitatum, capitate utricle

Codium capitatum, capitate utricles (re-drawn from Silva 1959)

Order Bryopsidales

Family Codiaceae

Codium duthieae P.C. Silva 1956: 275-277.

Thallus dark green, erect, up to 30 (-60) cm tall, dichotomously branched up to 10 times or more, branches often flattened at dichotomies, otherwise terete. Dichotomies up to 40 m wide, branches 5-10 (-14) mm in diameter. Utricles 800-1800 µum long and may vary in diameter from about 180-500 (-720) µm, apices broadly rounded or subtruncate. Hairs or hair scars occasional but may be numerous, in zone short distance below apices of utricles. Gametangia lanceolate-ovoid, 270-430 (-500) µm long, several per utricle, each on pedicel, in zone near middle of utricle.

Collections, ecology and regional distribution

Rock pools , lower eulittoral to shallow sublittoral. Found along the whole South African coast (Coppejans et al. 2005).

World distribution

Oman, Vietnam, Australia, New Zealand, Southern Africa: Namibia, Kenya, Mozambique (Guiry in Guiry & Guiry 2014).

Type locality

Strandfontein, False Bay, South Africa (Silva et al. 1996).

Note: the correct spelling of the name of this species is C. duthieae.

Codium duthieae, habit. Note widened dichotomies. Thallus partly covered with small red epiphytes.

 Codium duthieae, utricles

 Codium duthieae, gametangium

 Codium duthieae, subtruncate utricles with gametangia near mid-point

Order Bryopsidales

Family Codiaceae

Codium extricatum P.C. Silva 1959: 145-147

Thallus dark green, erect, firm, up to 50 cm tall, dichotomously branched up to 14 times, branches often flattened in lower thallus, terete above, up to 8 mm in diameter tapering to 1.5-2 mm at apices. Utricles subcylindrical to club-shaped, 450-880 µm long, 125-280 (-325) µm diameter, apices truncate or slightly rounded, utricle wall at apex often markedly thickened. Hairs or hair-scars common, one to several per utricle, disposed in zone 40-100 µm below apex. Gametangia lanceolate-ovoid, 240-330 µm long, 1-3 per utricle, each on short pedicel arising near middle of utricle.

Collections, ecology and regional distribution

Found in rock pools, lower eulittoral and sublittoral fringe, from Cape Agulhas to Umpangazi (near Cape St Lucia), KZN (22-55).

World distribution

Disjunct distribution: South Africa, Kenya, Lord Howe Island (NZ) Queensland, Australia, and Norfolk Island (Guiry in Guiry & Guiry 2014).

Type locality: Qolora River mouth, Eastern Cape (Silva 1959).

Codium extricatum, habit

 Codium extricatum, utricle showing thick wall at apex

 Codium extricatum, utricle with gametangium

Order Bryopsidales

Family Codiaceae

Codium fragile subsp. capense P.C. Silva 1959: 153-157.

Thallus dark green, erect, 10-30 cm tall, dichotomously branched up to 10 x or more, branches terete throughout or slightly flattened near base of thallus, 5-8 (-14) mm in diameter, tapering at apices. Utricles club-shaped, 730-1100 µm long, 130-270 (-355) µm wide, apices characteristically pointed, with a sharp mucro. Hairs or hair-scars common, 1-2 (-3) per utricle, borne short distance below apex. Gametangia lanceolate-ovoid to cylindrical, 275-460 µm long, borne on pedicels in zone near middle of utricle.

Collections, ecology and regional distribution

Orange River to Tsitsikamma (1-32). Found in lower eulittoral zone and rock pools.

World distribution

A southern African endemic, also found in Namibia. The species C. fragile is found in northern and southern hemisphere temperate seas: many records appear to be recent introductions.

Type locality: Melkbosch, Western Cape (Silva et al. 1996).

 Codium fragile subsp capense, herbarium specimen.

Codium fragile subsp capense, detail of utricles with characteristic sharp points (mucros). Re-drawn after Silva (1959).

Order Bryopsidales

Family Codiaceae

Codium incognitum P. C. Silva 1959: 118.

Thallus dark green, up to 5 mm thick, applanate, attached to substratum over most of its under-surface. Utricles in clusters, 720-2400 um long, 110-165 (-260) µm wide, cylindrical, often swollen some distance below apex; apices truncate or slightly rounded. Hairs or hair-scars not seen. Gametangia cylindrical to spindle-shaped, 260-340 (-390) µm long, 1-3 per utricle, borne on pedicels 300-470 µm below apex.

Collections, ecology and regional distribution

Recorded from Robberg (Plettenberg Bay) to Haga Haga area (31-43). Found in eulittoral and sublittoral zones.

World distribution: A South African south coast endemic (Guiry in Guiry & Guiry 2014).

Type locality: Robberg, Plettenberg Bay (Silva 1959).

Codium incognitum, herbarium specimen

 Codium incognitum, herbarium specimen

 Codium incognitum, utricles (re-drawn from Silva 1959)

Order Bryopsidales

Family Codiaceae

Codium isaacii P. C. Silva 1959: 151.

Thallus dark green, erect, up to 20 cm tall, dichotomously branched up to 8 times, branches terete, 3-6 mm in diameter. Utricles single, stout, subcylindrical to club-shaped, 500-900 (-1050) µm long, 185-400 (-590) µm in diameter, apices rounded to truncate. Hairs or hair scars not seen. Gametangia stoutly spindle-shaped or lanceolate-ovoid, 260-365 µm long, several per utricle, on pedicels, borne at or just below middle of utricle.

Collections, ecology and regional distribution

A cool-water species, found from the Orange River to Stilbaai area (1-25), from the lower eulittoral into the sublittoral.

World distribution: A southern African endemic, also in Namibia (Guiry & Guiry 2014).

Type locality: Lectotype specimen from Melkbosch, Western Cape (Silva et al. 1996).

Codium isaacii, herbarium specimens

 Codium isaacii, utricle

 Codium isaacii, utricles (re-drawn from Silva (1959).

Order Bryopsidales

Family Codiaceae

Codium lucasii subsp. capense P.C. Silva 1959: 111-115.

Thallus very dark green, firm, slippery, applanate, irregularly lobed, 2.5-5 mm thick and up to several cm in diameter, adhering tightly to substratum. Utricles in large clusters, 500-800 (-1100) µm long, 60-105 (125) µm in diameter, cylindrical, slightly to markedly constricted below the apex, apices truncate or rounded. Hairs or hair-scars common on older parts, in band somewhat below apex. Gametangia lanceolate-ovoid to fusiform, 215-370 µm long, 1-2 per utricle, on pedicels below apex.

Collections, ecology and regional distribution

Recoded from Strand (False Bay) to northern KwaZulu-Natal (18-58), in rock pools and the lower eulittoral zone.

World distribution: Also recorded from Mozambique, Kenya, Australia and New Zealand (Guiry & Guiry 2014). However, Coppejans et al. (2005), citing Van den Heede & Coppejans 1996, do not recognize subspecific taxa in C. lucasii because of a ‘continuum of utricle sizes along the east African coast’.

Type locality: Shaka’s Rock, KZN, South Africa (Silva et al. 1996).

Codium lucasii, habit

Codium lucasii, utricles – note slight constrictions below apices

Order Bryopsidales

Family Codiaceae

Codium megalophysum P.C. Silva 1959: 125-127

Thallus shiny light green, hemispherical or globose, to 10 cm diameter, loosely attached to rock by tuft of rhizoids; old thalli with central depression or hole. Utricles visible to naked eye, cub-shaped, with knobby outgrowths in upper half, 5-12 mm long, 1-3.5 mm in diameter. Hairs or hair-scars absent. Gametangia ellipsoid, ovoid or flask-shaped, 540-1030 µm long, on short pedicels, several per utricle, borne below apex.

Collections, ecology and regional distribution

Port Elizabeth to northern KZN (36-58). Common in the sublittoral fringe; recorded down to 40m depth in KZN (Coppejans et al. 2005).  

World distribution: South African endemic (Guiry & Guiry 2014).

Type locality: Port St Johns, Eastern Cape (Silva et al. 1996).

Codium megalophysum, habit

Order Bryopsidales

Family Codiaceae

Codium papenfussii P. C. Silva 1959: 122-124.

Thallus dark green, smooth, very firm, 2-8 cm in diameter, hemispherical to subglobose when young becoming hollow and flattened with age, loosely attached to substratum by tuft of rhizoids. Mature utricles in clusters, cylindrical to slightly club-shaped, with prominent bulge below the apex, 3-5 mm long, diameter about 700 µm at bulge, apices of young utricles rounded, becoming truncate with age. Hairs or hair-scars absent. Gametangia lanceolate-ovoid, 480-590 µm long, 1- per utricle, borne on pedicels below apices.

Collections, ecology and regional distribution

From Camps Bay, Cape Peninsula, eastward to southern KZN (16-49). Generally a deeper sublittoral species.

World distribution: South African endemic (Guiry & Guiry 2014).

Type locality: Kalk Bay (False Bay), Western Cape (Silva et al. 1996).

Codium papenfussii, habit

 Codium papenfussii, utricles (re-drawn from Silva 1959).

Order Bryopsidales

Family Codiaceae

Codium pelliculare P. C. Silva 1959: 127-130

Thallus dark green, applanate, thin (1.5-3 mm), firm, often with rounded lobes, up to 15 cm diameter, becoming hollow and sand-filled when old. Outer layer comprising primary and secondary utricles; primary utricles arising from branches of central hyphal system, secondary utricles arising from middle or lower part of primary utricles and forming clusters. Utricles club-shaped, widening at apex, often constricted below apex, 700 - 1100 (-1350) µm long, older utricles often broader near middle; apices truncate or rounded. Hairs or hair-scars absent. Gametangia lanceolate-ovoid to fusiform, 230 – 410 µum long, 1-3 per utricle, borne on pedicels.

Collections, ecology and regional distribution

A South African south coast endemic, recorded from Arniston (Western Cape) to Port St. Johns, Eastern Cape (23-46). Found in pools in the lower eulittoral.

Type locality: East London (Silva et al. 1996).

Note: Silva (1959) records that C. pelliculare is unique in habit and anatomy. Its membrane-like appearance is striking, and ‘a plug forms at the base of each developing utricle rather than at the point of departure of the lateral branch (new growing point) from the old apex, as in all other species of the genus’.

Codium pelliculare. The very thin thallus is apparent in this herbarium specimen.

 Codium pelliculare, utricles (re-drawn from Silva 1959)

Order Bryopsidales

Family Codiaceae

Codium platylobium Areschoug 1854: 367

Thallus dark green, flaccid, erect, stipe terete at base, flattening and widening to bear flattened branches of up to 8 orders, branches 3-24 cm wide, 1.5 – 2 mm thick, up to 2 m long, linear-lanceolate, acute in young plants becoming blunt when old, old specimens often with many proliferations from margins. Utricles cylindrical or slightly club-shaped, 500-750 (-840) µm long, apices rounded or truncate, hairs or hair-scars occasional. Gametangia lanceolate-ovoid or ellipsoidal, 180-250 µm long, several per utricle, borne on conspicuous pedicels near or below middle of urticles.

Collections, ecology and regional distribution

Table Bay to southern KZN (Mtwalume River – Port Shepstone) (15-49).

A distinctive and characteristic species on the south coast, this is the only flat-bladed, erect Codium on the South African coast. It occurs in intertidal rock-pools and the shallow sublittoral zone.

World distribution: Also recorded from Senegal and Korea (Guiry & Guiry 2014).

Type locality: Port Elizabeth (lectotype) (Silva et al. 1996).

Codium platylobium (with red patches of the epiphyte Placophora binderii).

 Codium platylobium, utricles (reproduced from Stegenga et al. 1997).

Order Bryopsidales

Family Codiaceae

Codium pocockiae P. C. Silva 1959: 138-140

Thallus erect, dark green, 4-10 cm tall, dichotomously branched but two dichotomies usually unequally developed so that branching appears cervicorn (horn-like), branches of uneven width, slightly flattened in lower part, 3-7 mm wide. Utricles slender, club-shaped, 500-1050 (-1250) µm long, apices rounded to subacute, often asymmetrically thickened. Hairs or hair-scars common, two to several per utricle, borne zone slightly below apex. Gametangia ellipsoidal, lanceolate-ovoid or cylindrical, 225-260 (-350) µm long, each on short pedicel above the middle of utricle.

Collections, ecology and regional distribution

Recorded from Hluleka (Transkei) northwards through KwaZulu-Natal (45-58). Found in the lower eulittoral and rock pools.

World distribution: Also recorded from Mozambique, Kenya, Easter Island and Chile (Guiry & Guiry 2014).  

Type locality: Port St. Johns, Transkei (Silva et al. 1996).

Note: Distinguished anatomically by ‘long clavate utricles with markedly and often asymmetrically thickened apices’ and in habit by ‘divaricately dichotomous branching in which the two branches of a dichotomy are often very unequally developed and of uneven width’ (Silva 1959).

Codium pocockiae, herbarium specimens.

 Codium pocockiae, utricles (re-drawn from Silva 1959).

Order Bryopsidales

Family Codiaceae

Codium prostratum Levring 1938: 16-17

Thallus dark green, creeping (repent) and rarely erect, subdichotomously branching, up to 16 cm across, branches terete or slightly compressed, overlapping, 3-9 mm thick. Utricles subcylindrical or slightly club-shaped, often tapering towards the base, 720-1310 µm long; apices truncate to slightly rounded. Hairs or hair-scars abundant, 1-9 per utricle, borne just below apex. Gametangia usually subcylindrical, or lanceolate-ovoid, 235-365 µm long, 1-3 per utricle, on pedicles, above middle of utricles.

Collections, ecology and regional distribution

Dwesa, Transkei, through KZN (44-58), in lower eulittoral zone and rock pools.

World distribution: Western Indian Ocean (Mozambique, Kenya, Mauritius, Réunion) also Fiji (Silva et al. 1996, Guiry & Guiry 2014).

Type locality: Isipingo Beach near Durban, KZN (Silva 1959).

Note: the creeping, subdichotomously branched thallus and long, slender utricles are distinctive of this species among southern African Codium species.

Codium prostratum, herbarium specimens

 Codium prostratum, utricles

Order Bryopsidales

Family Codiaceae

Codium spongiosum Harvey 1855: 565

Thallus soft, applanate or cushion-like, undulate to cerebriform, 6-10 cm in diameter, to 2 cm thick, adhering loosely to substratum. Utricles in large clusters, those of final orders cylindrical or club-shaped, 1.4 – 2 mm long, 130-300 µm in diameter, apices subtruncate to rounded. Hairs or hair-scars abundant, in band slightly below apices. Gametangia lanceolate-ovoid or flask-shaped, 215-360 µm long, several per utricle, on short pedicels below hair zone. Thallus becoming gelatinous in liquid preservative.

Collections, ecology and regional distribution

From Morgan Bay through Transkei and KwaZulu-Natal to Mozambique (43-58).

Found in crevices in rock and around rims of tide pools, uncommon (Silva 1959).  

World distribution

Apparently very widespread in temperate and tropical seas; in Africa also recorded from Mozambique, Mauritius (W. Guiry in Guiry & Guiry 2014).

Type locality: King George’s Sound, Western Australia (Silva et al. 1996).

Note: Silva (1959) states that the South African material is anatomically indistinguishable from the Austalian material but thalli here tend to be smaller and far less common than in Australia.

Codium spongiosum, herbarium specimen.

 Codium spongiosum, utricles (re-drawn from Silva 1959).

Order Bryopsidales

Family Codiaceae

Codium stephensiae Dickinson 1932: 131-136

Thallus dark green, applanate, procumbent, velvety but tough, up to 30 cm in daimeter, 2.4 – 5 mm thick, adhering centrally and here and there on otherwise free lobes by patches of rhizoids; young lobes rounded or with blunt teeth, older lobes becoming irregularly or symmetrically cleft, largely free from substratum. Utricles of dorsal surface in large clusters, 315-1500 µm long, with attenuated subapical contriction giving a unique ‘ninepin’ shape, broadening to maximum diameter below constriction, apices truncate or slightly depressed or rounded. Utricles of ventral surface shorter and less constricted. Hairs or hair-scars scarce, 1-3 per utricle, at top of constriction. Gametangia cylindrical, 200-325 µm long, one (rarely two) per utricle, on short pedicel below constriction.

Collections, ecology and regional distribution

Mainly a south coast species, but recorded from St. Helena Bay (west coast) to Port Shepstone area, southern KZN (11-48). Found in lower sublittoral pools and gulleys and in the shallow sublittoral zone.

World distribution: South African endemic.

Type locality: Kommetjie, Cape Peninsula (lectotype) (Silva et al. 1996).

Note: C. stephensiae differs from other South African adherent Codium species in its development of isobilateral lobes. Silva (1959) further points out that C. stephensiae differs from the superficially similar C. lucasii in several respects: the former is largely free from the substratum, and has a cortical layer of utricles on both surfaces, while the latter is attached except at the margins, and only has a cortex on the upper surface.  

Codium stephensiae, habit

 Codium stephensiae, utricles (note characteristic ninepin shape) with gametangia

 Codium stephensiae, utricles (reproduced from Stegenga et al. 1997).

Order Bryopsidales

Family Codiaceae

Codium tenue (Kützing) Kützing 1856: 33-34

Thallus light green, bushy, erect, flaccid, to 45 cm tall, closely divaricately dichotomously branched, dichotomies flattened and widened (to 2.2 cm in lower thallus), interdichotomies terete, 4-5 mm wide in lower thallus, narrowing to 1-2 mm near branch tips. Utricles from mid-thallus turbinate, quadrate (rectangular), obovate or pyriform, 330-450 µm long, and pyriform or club-shaped, 480-760 µm long, apices broadly rounded or slightly flattened. Hairs or hair-scars frequent, 1-3 per utricle, just below apex. Gametangia ovoid or sometimes spindle-shaped, 122-238 µm long, on pedicels, usually below middle of utricles.

Collections, ecology and regional distribution

Recorded from Knysna to Port Shepstone (30-49). Usually confined to estuaries, where it can be abundant, but also occasionally found in freshwater-affected tidal pools.

World distribution: Also recorded from Mauritius, Senegal, Sudan and various localities in the Indian and Pacific Oceans (M.D. Guiry in Guiry & Guiry 2014).

Type locality: Eastern Cape Province, South Africa (Silva et al. 1996).

Note: For more detailed description, see Silva (1959).  

Codium tenue, habit

 Codium tenue, utricles

Order Bryopsidales

Family Halimedaceae

Thallus divided into segments that are always calcified to some degree. Structurally, the thallus of comprises a single, multinucleate cell that forms a highly branched system of filaments running through and linking the segments. Life history diplontic, with gametangia formed on the surface of segments

Genus Halimeda Lamouroux

Thallus erect, arising from dense, felt-like rhizoidal holdfast; repeatedly branched, comprising series of calcified segments (internodes) joined by small, uncalcified, flexible nodes; branches flat or compressed. Structure of a core of medullary filaments surrounded by layers of closely adherent cortical filaments (utricles). Reproduction is by flagellate gametes that are formed in stalked gametangia on the margin or surface of segments. After release of gametes, segments lose their colour and are shed. This tropical genus comprises about 38 currently recognized species worldwide (Guiry & Guiry 2012) The account in Coppejans et al. (2005) covers most of the species recorded in South Africa, including the two found on our south coast.  

Key to species

1a. Segments usually longer than broad (wedge-shaped), separated by short stalk zones or collars

H. cuneata

1b. Segments usually broader than long, stalk zones absent; upper rim of older segments grooved

H. tuna

Order Bryopsidales

Family Halimedaceae

Halimeda cuneata Hering in Krauss 1846: 214

Plants light to dark green, erect, up to 20 cm long, composed of flat calcified segments arising from a dense rhizoidal holdfast mass. Segments up to about 10 mm wide and 15 mm long, usually smaller especially distally: cuneate or sometimes obovate, segments in a single plane, thalli branched up to 4 times. In H. cuneata segments are usually separated by a short ‘stalk zone’ which may be calcified into a small, distinct collar; daughter segments may arise anywhere along the distal edge of mother segments. Rims of older distal segments may be grooved.  

Collections, ecology and regional distribution

From Tsitsikamma eastward to northern Kwazulu-Natal (34-58). Found in the sublittoral fringe and sublittoral zone.

Type locality: Natal Bay, South Africa (Silva et al. 1996).

World distribution: along the coast of east Africa to Somalia and fairly widespread in the world’s tropical and warm temperate oceans (Guiry in Guiry & Guiry 2014).

Halimeda cuneata

Halimeda cuneata, fertile segments

Order Bryopsidales

Family Halimedaceae

Halimeda tuna (J. Ellis & Solander) J. V. Lamouroux 1816: 309

Plants bright green, erect, branched 2-3 times, up to 10 cm tall. Segments flat, calcified, broader than long, 3-14 mm long; wedge-, kidney-, or disc-shaped; daughter segments arising anywhere along the distal rim of mother segments, stalk zone or collar between segments absent, distal rim of older segments sometimes grooved. For details of internal structure see Coppejans et al. (2005).

Collections, ecology and regional distribution

A solitary species, found in the sublittoral or sublittoral fringe. Occasionally found from central Transkei (Hluleka) northward, but common in northern Kwazulu-Natal (45-58).

World distribution: extends along the east African coast to Somalia, and is widespread in the tropical and some warm temperate regions of the world (Guiry in Guiry & Guiry 2014).

Type locality: Mediterranean Sea (Silva et al. 1996).

Halimeda tuna, herbarium specimen

 Halimeda tuna, habit (northern KZN)

Order Bryopsidales

Family Pseudocodiaceae

Monogeneric family: characters as for genus. The family was created to accommodate the genus, which is anatomically intermediate between Halimeda and Codium.

Genus Pseudocodium Weber-van Bosse

Thallus erect, comprising holdfast and branched cylindrical or compressed axes. Anatomically comprising a core (medulla) of siphons that produce a cortex of swollen, adherent branches (utricles) that are polygonal or hexagonal in surface view.

Pseudocodium devriesii Weber-van Bosse 1896: 209-212

Thalli erect, dark green, somewhat flaccid, cylindrical at base, 1-3 mm wide, compressed distally, dichotomously branched up to 8 times. Utricles tightly adherent and more or less polygonal in surface view. Spherical gametangia develop from the medullary siphons (Coppejans et al. 2005).

Collections, ecology and regional distribution

Common in lower eulittoral, rock pools, sublittoral fringe and shallow sublittoral. Found from East London through to northern KwaZulu-Natal (41-58).

World distribution

South Africa, Mozambique, Madagascar, as well as subtidally in Oman and Western Australia (DeClerck et al. 2008).

Type locality: Isipingo Beach, near Durban (De Clerck et al. 2008).

 Pseudocodium devriesii, Double Mouth, habit.

 Pseudocodium devriesii, Double Mouth, showing branching pattern.

Order Bryopsidales

Family Udoteaceae

Thallus coenoctic, filaments froming a flat, blade-like thallus, usually calcified. Cells containing chloroplasts and amyloplasts (storage bodies).

Genus Udotea J. V. Lamouroux 1812: 186

Thallus of erect, calcified blades and stalks and uncalcified rhizoidal holdfasts. Anatomy of filaments; stalk of longitudinal siphons with cortex formed by lateral branches, blades of dichotomously-branched siphons with various degrees of branching that may be species-specific. Reproduction by release of filament contents into gametangia; thallus thought to die after gamete release. A tropical-subtropical genus with about 39 currently recognised species (Guiry & Guiry 2014).

Udotea orientalis A. Gepp & E.S. Gepp 1911: 119-120

Thallus green, erect, fan-shaped or rounded, calcified and stiffish, 20-40 mm tall, with short stipe (5-15 mm) and holdfast of dense rhizoids. Blade usually with concentric lines, margin often split. Filaments of blade about 40 µm in diameter, tightly interwoven, dichotomously-branched and with constrictions but lacking lateral outgrowths.

Collections, ecology and regional distribution

From Hluleka northward, common in northern KwaZulu-Natal (46-58). Attached to rock in pools, sublittoral fringe and sublittoral zone, as solitary individuals or groups.

World distribution: On the east African coast through Mozambique to Somalia; fairly widespread in the Indo-West Pacific (see references in Guiry & Guiry 2014).

Type locality: syntype localities in various places in the Indian and Pacific Oceans (Silva et al. 1996).

Udotea orientalis, KZN specimens.

 Udotea orientalis, showing concentric growth lines.

Order Bryopsidales

Family Derbesiaceae

Derbesia hollenbergii W.R.Taylor 1945: 75, pl. 1: figs 7-9

Plants medium green, caespitose, with an irregularly branched rhizoidal basal system and many erect filaments up to ca. 5 cm tall. Filaments 50-100 µm in diameter, infrequently branched. Chloroplasts round to spindle-shaped, 5-10 µm long. Sporangia formed laterally on the erect filaments, single, stalked; sporangia squat, with truncate apex, 100-120 x 90-100 µm, spores not seen.

Collections, ecology and regional distribution

Recorded from Muizenberg (False Bay) to Durban (18-51), from rock pools and the lower eulittoral zone.

World distribution: Also known from Mexico, Panama and the Galapagos (Guiry & Guiry, 2012).

Type locality: Galapagos, Ecuador (Taylor 1945).

Derbesia hollenbergii, Hluleka, with sporangia (stained slide material).

Derbesia hollenbergii, Hluleka, sporangium and stalk (stained slide material).

Derbesia hollenbergii, Hluleka, detail of sporangium and stalk (stained slide material).

Derbesia hollenbergii, zoosporangia (reproduced from Stegenga et al. 1997).

Order  Bryopsidales

Family  Derbesiaceae

Derbesia marina (Lyngbye) Solier 1846: 453

Plants caespitose, with an irregularly branched rhizoidal basal system, and with many erect filaments up to 10 mm high, infrequently branched . Filaments 40-60 µm in diameter. Chloroplasts rounded to ellipsoid, 2-5 µm long. Sporangia formed laterally on the erect filaments, simple or stalked, or formed consecutively in small sympodial clusters: sporangia ovoid to ellipsoidal, 100-150 x 60-100 µm; individual spores about 20 µm in diameter.  

Collections, ecology and regional distribution

Recorded from Muizenberg (drift attached to Ecklonia – Stegenga et al. 1997) to Hluleka (18-45). Found in lower eulittoral rock pools.

World distribution: widespread in temperate and tropical waters (Guiry & Guiry 2012).

Type locality: Faeroe Islands (Silva et al. 1996).

Note: Our records of D. marina include those previously reported as Derbesia ryukyuensis Yamada & Tanaka (Bolton & Stegenga 1987; Anderson & Stegenga 1989). Derbesia ryukyuensis is now assigned to the genus Pedobesia MacRaild & Womersley, and has a calcified, discoid basal system, which we have not seen in South African material. See also note in Stegenga et al. (1997).

Derbesia marina, Bird Island (slide material)

 Derbesia marina, Bird Island (slide material), detail of sporangium

 Derbesia marina, ruptured sporangium wall and spores

Halicystis phase of a Derbesia sp. (Glen Muir: vesicles about 7 mm in diameter).

Derbesia marina, zoosporangia (reproduced from Stegenga et al. 1997).

REFERENCES

References to Introduction and Chlorophyta

Agardh, C.A. 1811. Dispositio algarum Sueciae, quam publico examini subjiciunt Carl Adolph Agardh... & Johannes Bruzelius, Scanus. Die xi decembris mdcccxi. p. ii. h. & l.s. pp. Pars 2: [i], 17-26. Lund: Berling.

Agardh, C.A. 1823. Species algarum rite cognitae, cum synonymis, differentiis specificis et descriptionibus succinctis. Volumen primum pars posterior. pp. [vii-viii], [399]-531. Lundae [Lund]: ex officina Berlingiana.

Agardh, J.G. 1873. Till algernes systematik. Nya bidrag. Lunds Universitets Års-Skrift, Afdelningen for Mathematik och Naturvetenskap 9(8): 1-71.

Anderson, R. J., Simons, R. H., Jarman, N. G. & Levitt, G.J. 1991. Gelidium pristoides in South Africa. Hydrobiologia 221: 55‑66.

Anderson, R.J. & Stegenga, H. 1989. Subtidal algal communities at Bird Island, Eastern Cape, South Africa. Botanica.Marina 32: 299-311.

Areschoug, J.E. 1850. Phyceae extraeuropaeae exsiccatae. Vol. 1 pp. 1-30. Uppsala.

Areschoug, J.E. 1851. Phyceae capenses, quarum particulam primam, venia ampliss. philos. facult. Upsaliens., praeside J. E. Areschoug... pro gradu philosophico p.p. Johannes Conradus Carlberg gothoburgensis. In auditorio Gustaviano die vii maj mdccli. H.A.M.S. pp. 1-32. Upsaliae [Uppsala]: excudebat Reg. Acad. Typographus.

Areschoug, J.E. 1854. Phyceae novae et minus cognitae in maribus extraeuropaeis collectae. Nova Acta Regiae Societatis Scientiarum Upsaliensis, series 3 1: 329-372.

Armitage, P.R., Nelson, W.A. & Sutherland, J.E. 2017. Mismatch of morphological and molecular identifications in native and invasive subspecies of Codium fragile (Bryopsidophyceae, Chlorophyta). Journal of Phycology 53(1): 218-229.

Bally, R., McQuaid, C.D. & Brown, A.C. 1984. Shores of mixed sand and rock: an unexplored marine ecosystem. South African Journal of Science, 80: 500-503.

Barton, E.S. 1893. A provisional list of the marine algae of the Cape of Good Hope. Journal of Botany, London, 31: 53-56,81-84, 110-114, 138-144, 171-177, 202-210.

Boedeker, C., Leliaert, F & Zuccarello, G.C. 2016. Molecular phylogeny of the Cladophoraceae (Cladophorales, Ulvophyceae), with the resurrection of Acrocladus Näegeli and Willeella Børgesen, and the description of Lurbica gen.nov. and Pseudorhizoclonium gen.nov. Journal of Phycology 52: 905-928.

Bolton, J. J., Leliaert, F, De Clerck, O, Anderson, R.J., Stegenga, H., Engledow, H.E. & Coppejans, E. 2004. Where is the western limit of the tropical Indian Ocean seaweed flora? An analysis of intertidal seaweed biogeography on the east coast of South Africa. Marine Biology, 144, 51-59.

Bolton, J.J., Robertson-Andersson, D.V., Shuuluka, D. & Kandjengo, L. 2009. Growing Ulva (Chlorophyta) in integrated systems as a commercial crop for abalone feed in South Africa: a SWOT analysis. Journal of Applied Phycology 21: 575-583.

Bolton, J. J. & Stegenga, H. 1987. The marine algae of Hluleka (Transkei) and the warm temperate/sub-tropical transition on the east coast of southern Africa. Helgoländer Meeresuntersuchungen 41: 165-183.

Bolton J.J. & Stegenga, H. 2002. Seaweed biodiversity in South Africa. South African Journal of Marine Science, 24, 9-18.

Børgesen, F. 1930. Some Indian green and brown algae especially from the shores of the Presidency of Bombay. Journal of the Indian Botanical Society 9: 151-174, 10 figs, Plates I, II.

Børgesen, F. 1940. Some marine algae from Mauritius. I Chlorophyceae. Kongelige Danske Videnskabernes Selskab, Biologiske Meddelelser 15(4): 81.

Børgesen, F., 1933. Some Indian green and brown algae especially from the shores of the Presidency of Bombay. III. Journal of the Indian Botanical Society 12: 1-16.

Branch, G.M & Branch, M. 1981. The Living Shores of Southern Africa. Cape Town: C. Struik, 272 pp.

Branch, G. M., Griffiths, C. L., Branch, M.L. & Beckley, L.E. 2010. Two Oceans. A Guide to the Marine Life of Southern Africa. Struik Nature, Cape Town, 456 pp.

Breeman, A.M. 1988. Relative importance of temperature and other factors in determining geographic boundaries of seaweeds: experimental and phenological evidence. Helgolanders Meeresuntersuchungen, 42, 199-241.

Broady, P.A., Flint, E.A., Nelson, W.A., Cassie Coope, V., De Winton, M.D. & Novis, P.M. 2012. Phylum Chlorophyta and Charophyta: green algae. In: New Zealand inventory of biodiversity. Volume Three. Kingdoms Bacteria, Protozoa, Chromista, Plantae, Fungi. (Gordon, D.P. Eds), pp. 347-381. Christchurch: Canterbury University Press.

Brown, A.C. & Jarman, N.G. 1978. Coastal marine habitats. In: Werger, M.J.A. (ed.) Biogeography and Ecology of Southern Africa. Monographs in Biology 31: 1239-1277.

Burrows, E.M. 1991. Seaweeds of the British Isles. Volume 2. Chlorophyta. pp. [i]-xi, [1]-238, 60 figs, 9 pls. London: Natural History Museum Publications.

Carter, A.R. & Anderson, R.J. 1986. Seasonal growth and agar contents in Gelidium pristoides (Gelidiales, Rhodophyta) from Port Alfred, South Africa. Botanica Marina 29: 117-123.

Chapman, V.J. 1949. Some new species and forms of marine algae from New Zealand. Farlowia 3: 495-498, 5 figs.

Coppejans, E., Leliaert, F., & Verbruggen, H. 2005. Green Algae. In De Clerck, O., J.J.Bolton, R. J. Anderson & E. Coppejans, 2005. Guide to the Seaweeds of Kwazulu-Natal. National Botanic Garden of Belgium, Brussels (Scripta Botanica Belgica), pp 40-93.

Coppejans, E., Leliaert, F., Verbruggen, H., De Clerck O., Schils T., De Vriese T. & Marie T. 2004. The marine green and brown algae of Rodrigues (Mauritius, Indian Ocean). J. Nat. Hist. 38: 2959-3019.

De Clerck, O., Bolton, J.J, Anderson, R.J. & Coppejans, E. 2005. Guide to the Seaweeds of Kwazulu-Natal. National Botanic Garden of Belgium, Brussels (Scripta Botanica Belgica), 294 pp.

De Clerck, O., Verbruggen, H., Huisman, J.M., Faye, E.J., Leliaert, F., Schils, T. & Coppejans, E. 2008. Systematics and biogeography of the genus Pseudocodium (Bryopsidales, Chlorophyta), including the description of P. natalense sp. nov. from South Africa. Phycologia 47: 225-235.

De Toni, G.B. 1889. Sylloge algarum omnium hucusque cognitarum. Vol. I. Chlorophyceae. pp. [3]-12, [i]-cxxxix, 1-1315. Patavii [Padua]: Sumptibus auctoris.

Delile, A.R. 1813. Description de l'Égypte our recueile et des observations et des recherches qui ont été faites en Égypte pendant l'expédition de l'armée française, publié par les orderes de Sa Majesté l'Empereur Napoléon le Grand.Histoire naturelle. Tom. Second. Histoire naturelle. Vol. 2 (fasc. 2 'troisème livraison') pp. 145-320 [Flore d'Égypte, explication des plances], pls 1-62 [1826]. Paris: Imprimerie Impériale.

Dickinson, C.I. 1932. A new adherent Codium from South Africa. Revue Algologique 6: 131-136, 3 figs, Plate 3.

Gepp, A. & Gepp, E.S. 1911. The Codiaceae of the Siboga Expedition including a monograph of Flabellariaea and Udoteae Siboga-Expeditie Monographie LXII. pp. 1-150, 22 pls. Leiden: E.J. Brill.

Guiry, M.D. & Guiry, G.M. 2012-2017. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. http://www.algaebase.org; searched at various times September 2012 – August 2017.

Guiry, M.D. in Guiry, M.D. & Guiry, G.M. 2014. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. http://www.algaebase.org; searched September 2012 - July 2014.

Guiry, W. in Guiry, M.D. & Guiry, G.M. 2014. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. http://www.algaebase.org; searched June – July 2014.

Harper, I. S. and R. N. Pienaar 1985. Life history and cytological studies in Bryopsis flanaganii (Bryopsidales, Chlorophyceae) from the Natal coast. South African Journal of Botany 51: 401-407.

Harvey, W.H. 1849. Phycologia britannica, or, a history of British sea-weeds: containing coloured figures, generic and specific characters, synonymes, and descriptions of all the species of algae inhabiting the shores of the British Islands. pp. text with plates, pls CCXVII-CCLXX [217-270]. London: Reeve & Benham.

Harvey, W.H. 1855. Some account of the marine botany of the colony of western Australia. Transactions of the Royal Irish Academy 22: 525-566.

Harvey, W.H. 1860. Characters of new algae, chiefly from Japan and adjacent regions, collected by Charles Wright in the North Pacific Exploring Expedition under Captain James Rodgers. Proceedings of the American Academy of Arts and Sciences 4: 327-335.

Hayden, H.S., Blomster, J., Maggs, C.A., Silva, P.C., Stanhope, M.J. & Waaland, J.R. 2003. Linnaeus was right all along: Ulva and Enteromorpha are not distinct genera. European Journal of Phycology 38: 277-294

Hering, [K.] 1841. Diagnoses algarum novarum a cl. Dre. Ferdinand Krauss in Africa Australi lectarum. Annals and Magazine of Natural History [Series 1] 8: 90-92.

Jackson, L.F & Lipschitz, S. 1984. Coastal Sensitivity Atlas of Southern Africa. Cape Town, Government Printer. 34 charts.

Joska, M.A.P. 1992. Taxonomy of Ulva species (Chlorophyta) in the South Western Cape, South Africa. MSc Thesis, University of Cape Town, 95 pp. + appendices.

Krauss, F. [Krauss, C.F.F. von] 1846. Pflanzen des Cap- und Natal-Landes, gesammelt und zusammengestellt von Dr. Ferdinand Krauss. (Schluss.). Flora 29(14): 209-215.

Krellwitz, E.C.,Kowallik, K. V. and P.S. Manos 2001. Molecular and morphological analyses of Bryopsis (Bryopsidales, Chlorophyta) from the western North Atlantic and Caribbean. Phycologia 40: 330-339.

Kützing, F.T. 1843. Phycologia generalis oder Anatomie, Physiologie und Systemkunde der Tange... Mit 80 farbig gedruckten Tafeln, gezeichnet und gravirt vom Verfasser. pp. [part 1]: [i]-xxxii, [1]-142, [part 2:] 143-458, 1, err.], pls 1-80. Leipzig: F.A. Brockhaus.

Kützing, F.T. 1845. Phycologia germanica, d. i. Deutschlands Algen in bündigen Beschreibungen. Nebst einer Anleitung zum Untersuchen und Bestimmen dieser Gewächse für Anfänger. pp. i-x, 1-340. Nordhausen: W. Köhne.

Kützing, F.T. 1847. Diagnosen und Bemerkungen zu neuen oder kritischen Algen. Botanische Zeitung 5: 1-5, 22-25, 33-38, 52-55, 164-167, 177-180, 193-198, 219-223.

Kützing, F.T. 1849. Species algarum. pp. [i]-vi, [1]-922. Lipsiae [Leipzig]: F.A. Brockhaus.

Kützing, F.T. 1856. Tabulae phycologicae; oder, Abbildungen der Tange. Vol. VI pp. i-iv, 1-35, 100 pls. Nordhausen: Gedruckt auf kosten des Verfassers (in commission bei W. Köhne).

Kützing, F.T. 1857. Tabulae phycologicae; oder, Abbildungen der Tange. Vol. 7 pp. i-ii, 1-40, 100 pls. Nordhausen: Gedruckt auf kosten des Verfassers (in commission bei W. Köhne).

Kylin, H. 1947. Über die Fortpflanzungsverhältnisse in der Ordnung Ulvales. Kungl. Fysiografiska Sällskapets i Lund Förhandlingar 17: 174-182.

Lamouroux, J.V.F. 1809. Observations sur la physiologie des algues marines, et description de cinq nouveaux genres de cette famille. Nouveau Bulletin des Sciences, par la Société Philomathique de Paris 1: 330-333, fig. 2, pl. 6.

Lamouroux, J.V.F. 1816. Histoire des polypiers coralligènes flexibles, vulgairement nommés zoophytes. pp. [i]-lxxxiv, chart, [1]-560, [560, err], pls I-XIX, uncol. by author. Caen: De l'imprimerie de F. Poisson.

Le Jolis, A. 1863. Liste des algues marines de Cherbourg. Mémoires de la Société Impériale des Sciences Naturelles de Cherbourg 10: 5-168, pls I-IV.

Leliaert, F. & Coppejans, E. 2003. The marine species of Cladophora (Chlorophyta) from the South African east coast. Nova Hedwigia 76: 48-52.

Leliaert, F. De Clerck, O., Bolton J.J. & Coppejans, E. 2001. New records of the Chlorophyta from South Africa, with the emphasis on the marine benthic flora of KwaZulu-Natal. South African Journal of Botany 67: 450-459.

Leliaert, F., Millar, A.J.K., Vlaeminck, C. & Coppejans, E. 2007. Systematics of the green macroalgal genus Chamaedoris Montagne (Siphonocladales), with an emended description of the genus Struvea Sonder. Phycologia 46: 709-725.

Levring, T. 1938. Verzeichnis einiger Chlorophyceen und Phaeophyceen von Südafrika. Lunds Universitets Årsskrift, Ny Följd, Andra Afdelningen 34(9): 1-25, 10 figs, pls I-IV.

Linnaeus, C. 1753. Species plantarum, exhibentes plantas rite cognitas, ad genera relatas, cum differentiis specificis, nominibus trivialibus, synonymis selectis, locis natalibus, secundum systema sexuale digestas. Vol. 2 pp. [i], 561-1200, [1-30, index], [i, err.]. Holmiae [Stockholm]: Impensis Laurentii Salvii.

Lipkin, Y. & Silva, P.C. 2002. Marine algae and seagrasses of the Dahlak Archipelago, southern Red Sea. Nova Hedwigia 75: 1-90, 7 figs.

Lubke, R.A, Gess, F.W. & Bruton, M.N. 1988. A Field Guide to the Eastern Cape Coast. Wildlife Society of Southern Africa, Grahamstown. 520 pp.

Lutjeharms, J.R.E., Cooper, J. & Roberts, M. 2000. Upwelling at the edge of the Agulhas Current. Continental Shelf Research 20: 737-761.

Lüning, K. (1990) Seaweeds: their environment, biogeography and ecophysiology. Wiley, New York.

Maggs, C.A., Blomster, J., Mineur, F. & Kelly, J. 2007. Ulvaceae. In Brodie, J., Maggs, C. A. & D, M. John (eds). The green seaweeds of Britain and Ireland. British Phycological Society, 242 pp.

Marker, M.E. 1988. Geology and geomorphology. In: Lubke, R.A., Gess, F.W. & Bruton, M.N. (Eds). A Field Guide to the Eastern Cape Coast. Wildlife Society of Southern Africa, Grahamstown, pp. 9-18.

Martens, G. von 1866. Die Tange. In: Die Preussische Expedition nach Ost-Asien. Nach amtlichen Quellen. Botanischer Theil. ( Eds), pp. 1-152. Berlin: Verlag de Königlichen Geheimen Ober-Hofbuchdruckerei (R.Y. Decker).

Montagne, C. 1850. Pugillus algarum yemensium, quas collegerunt annis 1847-1849, clarr. Arnaud et Vaysière. Annales des Sciences Naturelles, Botanique, Troisième série 13: 236-248.

Müller, O.F. 1778. Flora danica. Vol. 5, fasc. 13 pp. 8, Plates 721-780. Havniae (Copenhagen).

Murray, G. 1891. On new species of Caulerpa, with observations on the position of the genus. Transactions of the Linnean Society of London, Second Series, Botany 3: 207-213, pls 52, 53.

Murray, G. 1896. A new species of Caulerpa. Journal of Botany, British and Foreign 34: 177-178, 1 fig.

Okamura, K. 1903. Contents of the "Algae Japonicae Exsiccatae" Fasciculus II. Botanical Magazine, Tokyo 17: 129-132.

O'Kelly, C.J., Kurihara, A., Shipley, T.C. & Sherwood, A.R. 2010. Molecular assessment of Ulva spp. (Ulvophyceae, Chlorophyta) in the Hawaiian Islands. Journal of Phycology 46(4): 728-735.

Papenfuss, G.F. 1960. On the genera of the Ulvales and the status of the order. Journal of the Linnean Society of London, Botany 56: 303-318, 21 figs, 6 pls.

Pocock, M.A. 1959. Letterstedtia insignis Areschoug. Hydrobiologia 14: 1-71, 5 figs, 2 plates.

Provan, J., Booth, D., Todd, N.P., Beatty, G.E. & Maggs C.A. 2008. Tracking biological invasions in space and time: elucidating the invasive history of the green alga Codium fragile using old DNA. Diversity and Distributions 14: 343-354.

Rull Lluch, J. 2002. Marine benthic algae of Namibia. Scientia Marina 66 (Supplement 3): 258 pp.

Silva, P.C. & Womersley, H.B.S. 1956. The genus Codium (Chlorophyta) in southern Australia. Australian Journal of Botany 4: 261-289, 16 figs, 3 plates.

Silva, P.C. 1959. The genus Codium (Chlorophyta) in South Africa. Journal of South African Botany 25: 101-165, 22 figs, Plates II-XVI.

Silva, P.C., Basson, P.W. & Moe, R.L. 1996. Catalogue of the benthic marine algae of the Indian Ocean. University of California Publications in Botany 79: 1-1259.

Smit, A.J., Roberts, M., Anderson, R.J., Dufois, F., Dudley, S.F.J., et al. 2013.A Coastal Seawater Temperature Dataset for Biogeographical Studies: Large Biases between In Situ and Remotely-Sensed Data Sets around the Coast of South Africa. PLoS ONE 8(12): e81944. DOI:10.1371/journal.pone.0081944.

Solier, A.J.J. 1846. Sur deux algues zoosporées formant le nouveau genre Derbesia. Revue Botanique, Duchartre 1: 452-454.

Stegenga, H., Bolton, J.J. & Anderson, R.J. 1997. Seaweeds of the South African west coast. Contributions from the Bolus Herbarium 18: 655 pp.

Stephenson, T.A. 1948. The constitution of the intertidal fauna and flora of South Africa, Part 3. Annals of the Natal Museum, 11(2), 207- 324 + 2 plates.

Stephenson, T.A. & Stephenson, A. 1972. Life between tidemarks on Rocky Shores. San Francisco: W.H. Freeman, 425 pp.

Tanner, C.E. 1980. Chloropelta Gen. Nov., an Ulvaceaous green alga with a different type of development. Journal of Phycology 16: 128-137.

Taylor, W.R. 1945. Pacific marine algae of the Allan Hancock Expeditions to the Galapagos Islands. Allan Hancock Pacific Expeditions 12: i-iv, 1-528, 3 figs, 100 pls.

Trevisan, V.B.A. 1842 '1841'. Sul geuere Bangia. Atti della Terza Riunione degli Scienziati italiani 1841: 478-481.

Troell, M., Robertson-Andersson, D., Anderson, R.J., Bolton, J.J., Maneveldt, G., Halling, C. & Probyn, T. 2006. Abalone farming in South Africa: An overview with perspectives on kelp resources, abalone feed, potential for on-farm seaweed production and socio-economic importance. Aquaculture 257: 266-281.

Van den Heede C. & Coppejans E. 1996. The genus Codium (Chlorophyta, Codiales) from Kenya, Zanzibar and the Seychelles. Nova Hedwigia 62: 389-417.

van den Hoek, C. 1963. Revision of the European species of Cladophora. Brill, Leiden.

Verbruggen, H., Brookes, M.J.L, & Costa, J.F. 2016. DNA barcodes and morphometric data indicate that Codium fragile (Bryopsidales, Chlorophyta) may consist of two species. Phycologia 56 (1): 54-62.

Waldron, H.N. & Probyn T.A. 2010. Nitrate supply and potential new production in the Benguela upwelling system. South African Journal of Marine Science 12: 29-39.

Weber-van Bosse, A. 1896. On a new genus of siphonean algae - Pseudocodium. Journal of the Linnean Society of London, Botany 32: 209-212, Plate 1.

Wilby, D. 2009. Shallow Subtidal Seaweed Communities of the Agulhas Marine Province of South Africa. MSc Thesis, Botany Department, University of Cape Town, 97pp.

Womersley, H.B.S. 1984. The marine benthic flora of southern Australia. Part I. pp. 329, 102 figs, 16 plates. Adelaide: Government Printer, South Australia.

Wulfen, F.X. 1803. Cryptogama aquatica. Archives de Botanique 3: 1-64, pl. 1.

Wynne, M.J. 2011. Proposal of the name Chaetomorpha vieillardii (Kütz.), n. comb., for a large-celled tropical Chaetomorpha (Chlorophyta). Pacific Science 65(1): 109-115.

Wynne, M.J. 2017. The reinstatement of Lychaete J.Agardh (Ulvophyceae, Cladophoraceae). Notulae Algarum 31: 1-4, 1 fig.

Wynne, M.J., Verbruggen, H. & Angel, D.J. 2009. The recognition of Caulerpa integerrima (Zanardini) comb. et stat. nov. (Bryopsidales, Chlorophyta) from the Red Sea. Phycologia 48(4): 291-301, 13 figs, 2 tables.

GLOSSARY

Bisexual:

having both sexes.

Blade:

a flattened, leaf-like part of the thallus.

Calcar:

spur subtending a cystocarp.

Carpogonium (pl. carpogonia):

the female sex structure in red algae.

Carpospore:

a spore, usually diploid, produced in the carpogonium. In red algae, it grows into a free-living tetrasporophyte.

Cerata:

dorsal appendages on some opisthobranch mollusks (sea slugs) that contain diverticula of the digestive gland. Serve as gills.

Chloroplast:

a cell organelle specialized for photosynthesis, the production of carbohydrates from carbon dioxide, water in the presence of light energy.

Coenocytic:

referring to a multinucleate cell, the coenocyte, derived when the nucleus divides but the cytoplasm does not.

Conceptacle:

a fertile cavity, often with a pore.

Cortex:

tissue external to the medulla, often an outer covering, of a blade.

Cryptostomata:

minute cavities in the outer cortex of Fucales containing hairs.

Cystocarp:

a structure in the female gametophyte of red algae consisting of diploid carposporophyte surrounded by gametophytic tissue. It may be a pigmented bump with or without an ostiole.

Dichotomous:

branching in pairs.

Dioecious:

bearing male and female reproductive structures on separate individuals.

Diploid:

having a normal (double or 2n) set of chromosomes.

Discoid:

disk shaped. Usually referring to the shape of holdfasts.

Distichous:

arranged in two rows on opposite sides of an axis.

Distromatic:

having two layers of cells.

Gametangium (pl. gametangia):

a structure that produces gametes.

Euryhaline:

able to withstand a wide range of salinities.

Eurythermal:

able to withstand a wide range of temperatures.

Filamentous:

a row of cells arranged end to end forming a hair-like thallus.

Gamete:

a sexual cell, male or female (e.g., sperm and eggs).

Gametophyte:

the haploid and sexual phase in the life history of an alga; produces gametes.

Haploid:

having a single set of chromosomes - half the normal number (1n).

Herbivory:

feeding on plants.

Holdfast:

the structure that attaches the alga to its substratum.

Intercallary:

occurring anywhere along the thallus except at the apex.

Intergeniculum (pl. intergenticula): a

calcified segment between the uncalcified joints of coralline algae.

Isomorphic:

having the same shape; looking alike.

Lanceolate:

shaped like a lance; several times longer than wide.

Laminarin:

a polysaccharide carbohydrate energy storage product in Laminaria.

Meristem:

a region of rapidly dividing, undifferentiated cells; an area of growth.

Midrib:

the middle rib of a blade.

Monoecious:

bearing male and female reproductive structures on the same individual.

Monostromatic:

having one layer of cells.

Oogonium:

a female reproductive cell (gametangium) that produces one or more female gametes (eggs).

Ostiole:

a pore.

Ovate:

egg-shaped.

Papilla (pl. papillae):

small rounded or pimple-like projections on a surface

Pericentral:

surrounding central axial cells.

Pinnate:

having similar parts arrange on opposite sides of an axis, like a feather.

Plastid:

a pigmented cell organelle (e.g., a chloroplast which contains chlorophyll).

Pneumatocyst:

a gas bladder or float of brown algae.

Receptacle:

the inflated tip of a branch that holds conceptacles (e.g. the swollen tip of Fucus).

Rhizoid:

a unicellular or filamentous structure for attachment.

Rhizome:

a horizontal, shoot-producing stem growing within the substrate.

Saxicolus:

growing on rocks.

Spermatangium (pl. spermatangia):

a cell in red algae that produces a single, nonflagellated, male gamete (the spermatium).

Spore:

a motile or nonmotile, asexual reproductive structure.

Sporophyll:

the part of the alga, usually a blade, which bears sporangia, the structure that produces spores.

Sporophyte:

the diploid phase in the life history of the alga; produces spores.

Sorus (pl. sori):

a cluster of reproductive structures.

Stipe:

the stem-like part of the thallus between the holdfast and the blade(s).

Stolon:

a runner growing out of the base of the alga capable of producing offshoots.

Substratum:

the material (such as rock) on which the alga is growing (substrate).

Tetraspore:

a spore, grouped in fours, produced by tetrasporophytes

Tetrasporophyte:

a phase in the life history of red algae that produces tetraspores.

Tertiary:

referring to a third stage.

Thallus:

the body of the alga.

Uniseriate:

having a single row of cells.

Utricle:

the inflated part of Codium that contains plastids.

Vegetative:

not associated with reproductive cells or sexual reproductive capacity.

Zygote:

a fertilized egg cell.

INDEX TO GENERA AND SPECIES

FAMILY ULOTRICHACEAE

Ulothrix flacca

FAMILY CHAETOPHORACEAE

Sporocladopsis novae-zelandiae

FAMILY KORNMANNIACEAE

Blidingia minima

FAMILY ULVACEAE

Letterstedtia insignis

Ulva genus

Ulva flexuosa

Ulva clathrata

Ulva compressa

Ulva fasciata

Ulva intestinalis

Ulva prolifera

Ulva rhacodes

Ulva rigida

Ulva tanneri

Ulva torta

Ulva uncialis

FAMILY ULVELLACEAE

Acrochaete sp

FAMILY CLADOPHORACEAE

Chaetomorpha genus

Chaetomorpha linum

Chaetomorpha aerea

Chaetomorpha antennina

Chaetomorpha natalensis

Chaetomorpha spiralis

Chaetomorpha vieillardii

Cladophora genus

Cladophora flagelliformis

Cladophora albida

Cladophora coelothrix

Cladophora lehmanniana

Cladophora radiosa

Cladophora rugulosa

Cladophora sericea

Cladophora sp1

Cladophora sp2

Rhizoclonium riparium

Willeella ordinata

FAMILY SIPHONOCLADACEAE

Chamaedoris genus

Chamaedoris delphinii

Chamaedoris auriculata

FAMILY VALONIACEAE

Valonia genus

Valonia aegagropila

Valonia macrophysa

FAMILY BRYOPSIDACEAE

Bryopsis genus

Bryopsis africana

Bryopsis caespitosa

Bryopsis hypnoides

Bryopsis myosuroides

Bryopsis plumosa

Bryopsis pusilla

FAMILY CAULERPACEAE

Caulerpa genus

Caulerpa filiformis

Caulerpa bartoniae

Caulerpa brachypus

Caulerpa holmesiana

Caulerpa racemosa

Caulerpa zeyheri

FAMILY CODIACEAE

Codium genus

Codium frag subsp cap frsc

Codium capitatum

Codium duthieae

Codium extricatum

Codium incognitum

Codium isaacii

Codium lucasii subsp capense

Codium megalophysum

Codium papenfussii

Codium pelliculare

Codium platylobium

Codium pocockiae

Codium prostratum

Codium spongiosum

Codium stephensiae

Codium tenue

FAMILY HALIMEDACEAE

Halimeda genus

Halimeda cuneata

Halimeda tuna

FAMILY PSEUDOCODIACEAE

Pseudocoium devriesii

FAMILY UDOTEACEAE

Udotea orientalis

FAMILY DERBESIACEAE

Derbesia hollenbergii

Derbesia marina

The Authors

From left: Rob Anderson, Herre Stegenga and John Bolton.

Brief biographies

Rob Anderson completed a PhD at the University of Cape Town in 1982, just after joining the Seaweed Unit in the SA Government fisheries department. Although much of his work involved commercial seaweed resources, he maintained a strong interest and has published in many aspects of seaweed biology and systematics. He has collaborated extensively with John Bolton, Herre Stegenga and others. Recently retired, he continues to surf, dive and enjoy the ocean.

Herre Stegenga completed his Ph D ("doctoraat") in 1979 at the Free University of Amsterdam. He published a Flora of the Dutch Seaweeds in 1983 (with Ivo Mol) and spent the next ten years mainly in South Africa (University of Cape Town, Rhodes University in Grahamstown), resulting in the publication of the Seaweeds of the South African West Coast (Stegenga, Bolton & Anderson 1997). After 1992 he revisited the RSA several times to collect material from the South Coast. Retired in 2012, he is still active in western European seaweed identification.

John Bolton is Emeritus Professor and Senior Research Scholar at the University of Cape Town, where he taught all aspects of phycology (the study of algae) for 35 years. His research interests include the diversity and biogeography of seaweeds, seaweed use and aquaculture, and the integrated aquaculture of seaweeds with marine animals. He is a former President of the International Phycological Society, and was awarded the Gilchrist Memorial Medal in 2017 in recognition of his contribution to South African marine science.

Acknowledgments

We are deeply indebted to Professor Michael Guiry and his colleagues who built and continue to maintain the incomparable algal website AlgaeBase.org – without it we would never have attempted this guide.

Our heartfelt thanks to Chris Boothroyd and
Derek Kemp for their enthusiastic and invaluable
technical help throughout the project.

We thank our colleagues and post-graduate students whose knowledge has been of enormous help, especially, Olivier De Clerck, Frederik Leliaert, Heroen Verbruggen and Eric Coppejans (Ghent University, Belgium), Enrico Tronchin (UCT) and others.

This work was funded from several sources over many years. FRD/NRF Post-doctoral bursaries sustained Herre Stegenga at Rhodes University and at UCT when he made many collections of specimens and microscope slides. DAFF (Department of Agriculture, Forestry and Fisheries) supported the participation of Anderson, Kemp and Boothroyd. SANPAD (South Africa Netherlands research Programme on Alternative Development) grants allowed us to train students and improve our collections from the south coast between 2001 and 2004. Various grants from NRF, UCT and DAFF all contributed through various projects. Most importantly, NRF funding of the SeaKeys Programme supported the development of this website. SANPARKS allowed us access to marine parks where important records were found. Finally, we thank the curators of the BOL and GRA herbaria for access to collections.

Colophon

Published by Seaweed Research Unit, Department of Biological Sciences, University of Cape Town and the Department of Agriculture, Forestry and Fisheries of South Africa.
Cape Town, South Africa

Typesetting: Seaweed Research Unit, Department of Biological Sciences, University of Cape Town, Rondebosch 7701, South Africa.