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Order Dictyotales

Family Dictyotaceae

Dictyota liturata J. Agardh 1848: 95

Thallus up to ca 20 cm tall, brown and non-iridescent; one to several uprights arising from a single rhizoidal attachment. While Tronchin & De Clerck describe this species as “completely erect”, Stegenga et al. (1997) note “a comparatively extensive prostrate foliose part”. Branching often appearing alternate because of uneven development of dichotomies; branches 4-7 mm wide, width similar throughout thallus but tapering slightly towards apices; apices rounded to truncate; margins smooth. Single layer of medullary cells, cortex usually single layered, but sometimes double-layered near edges. Medullary cells 60-130 µm long, 35-80 µm wide, 13-20 µm high; cortical cells approximately 10-22 µm wide, 13-18 µm high. Hair tufts common, as bundles of hairs in gaps in cortical cells, circular in surface view, ca. 150 µm in diameter.

Tetrasporangia frequent on both surfaces, clavate to sub-spherical, to 130 µm long, dividing tetrahedrally when mature, arranged in an irregular soral network. Oogonial sori ovoid, distributed over thallus surface, on average ca. 415 µm long x 270 µm wide. Antheridial sori not seen in our material, but described by Tronchin & De Clerck, (2005) as forming irregular patches surrounded by 2-3 rows of hyaline paraphyses. 

Description adapted from Tronchin & De Clerck, (2005). Note that their description differs in some respects from that in Stegenga et al. (1997). 

Collections, ecology and regional distribution

Recorded from Kommetjie to Sodwana Bay. Although Stegenga et al. (1997) quoted an eastern limit of Still Bay, recent DNA sequencing indicates a wider distribution along the whole south coast to northern KZN (pers. Comm. O. De Clerck) (17-58). Found in rock pools and the sublittoral zone down to at least 30 m depth (Tronchin & De Clerck, (2005).

World distribution: also recorded from certain Atlantic islands (Azores, Canary islands, madeira Salvage Islands, Tristan da Cunha) and Madagascar (references in M.D. Guiry in Guiry & Guiry 2016).

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

 


Dictyota liturata, Aliwal shoal, 18 m depth (BOL).


Dictyota liturata, intertidal rock pool, Palm Beach, KZN (BOL).


Dictyota liturata, Millers Point, False Bay, 3m depth (BOL).


Dictyota liturata, habit (reproduced from Stegenga et al. (1997). Note prostrate axes at base.


Dictyota liturata, . 1and 2 - Cross sections at thallus edge (note two-layered cortex in Fig.3). 3 Unilocular sporangia. Reproduced from Stegenga et al. (1997).


Dictyota liturata, Bordjiesrif, False Bay, showing extensive prostrate parts, as noted in the description of this species according to Stegenga et al. (1997). [Specimen D 2184)

 

References Dictyota liturata

Agardh, J.G. (1848). Species genera et ordines algarum, seu descriptiones succinctae specierum, generum et ordinum, quibus algarum regnum constituitur. Volumen Primum. Algas fucoideas complectens. pp. [i-vi], [i]-viii, [1]-363. Lundae [Lund]: C.W.K. Gleerup.

Guiry, M.D. in Guiry, M.D. & Guiry, G.M. 2016. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. http://www.algaebase.org; searched on 25 February 2016.

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.

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

Tronchin, E.M. & De Clerck, O. (2005). Brown algae. Phaeophyceae. Guide to the seaweeds of KwaZulu-Natal. Scripta Botanica Belgica 33: 95-129.

 

Cite this record as:

Anderson RJ, Stegenga H, Bolton JJ. 2016. Seaweeds of the South African South Coast.
World Wide Web electronic publication, University of Cape Town, http://southafrseaweeds.uct.ac.za; Accessed on 19 November 2018.