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Glossary

Acroblastic:
With branching originating from the apical cell.
Acropetal:
Developing from the base towards the apex: the youngest structures nearest the apex.
Adaxial:
Of lateral organs, the side lying nearest to the main axis, or furthest from it if the organ is deflexed.
Adelphoparasite:
A parasite which is phylogenetically closely linked to its host.
Angular:
With prominent angles, sharply ridged.
Anisogamy:
Sexual reproduction with motile gamete of unequal size; the larger is designated as the female while the smaller is male.
Antheridium:
The male gametangium in oogamus sexual organ.
Anticlinal:
In a direction perpendicular to the circumference/surface of the thallus.
Applanate:
Flattened or horizontally expanded.
Arcuate:
Curved like a bow; crescent-shaped.
Ascocyst:
A sac-like, enlarged cell, usually empty when old.
Attenuate:
Gradually tapering towards a point.
Axil:
The distal angle between a lateral branch, and the axis or organ bearing it.
Basipetal:
Developing from the apex towards the base: the youngest structures are nearest the base.
Bifurcate:
Forked; dividing more or less equally into two.
Bipinnate:
Pinnate branchlets arranged pinnately on the main branch.
Biseriate:
Arranged in two rows (especially of cells in a filament).
Bisporangia:
Sporangia in which two spores are produced.
Bisporiferous:
Bearing bisporangia.
Blade:
the broad, flatted part of the thallus.
Botryoid:
Having the appearance of a bunch of grapes.
Bullate:
Puckered.
Caespitose:
Matted, growing in turf or dense turf-like clumps.
Calcareous:
Impregnated with calcium carbonate.
Calcicolous:
Thrives in areas/habitats rich in calcium; growing on calcareous substrata.
Canaliculate:
Channeled; possessing a long groove.
Capitulum:
A swollen or knoblike tip.
Carposporangium:
A unicellular structure on the parasitic carposporohyte phase of members of the Florideophyceae, which gives rise to non-motile carpospores.
Cartilaginous:
Not easily compressed, yet flexible; like cartilage.
Catenate:
Chain-like.
Cervicorn:
Antler-like; branching one-sided.
Cicatrigenous:
Generated by a scar-cell or basal cells of a trichoblast (Rhodomelaceae).
Clavate:
Club-shaped.
Coenocytic:
Multinucleate and without cross walls.
Complanate:
Structures arranged in a single plane.
Conceptacle:
A cavity just below the surface of the thallus containing reproductive organs.
Convolute:
Rolled or twisted.
Cordate:
Heart shaped.
Cornucopiaeform:
Shaped like a goat’s horn or horn of plenty.
Cortex:
The outer layer of cells or tissue in a thallus, outside the medulla.
Corticated:
Having an outside layer of small cells.
Corymbose:
Having the shape of a cluster flattened transversely to the main axis.
Cruciate:
Divided in the shape of a cross (usually refers to tetrasporangia).
Crustose:
Lying closely and tightly fixed to the substratum.
Cuneate:
Wedge-shaped.
Cymose:
Type of distal branching in which the apices abort successively, growth being continued by laterals in each instance.
Decussate:
Having a branching pattern where paired opposite branches are perpendicular to the previous pair down the main axis.
Deltoid:
Shaped like a triangle.
Dentate:
Toothed.
Determinate:
Fixed or limited in number of parts or growth.
Dichotomous:
Divided or forked into two equal parts.
Diffuse (growth):
Growth in almost any part of the thallus, not localized.
Digitate:
Branched or split like the fingers of a hand.
Dioecious:
Having male and female reproductive structures on separate individuals.
Diplobiontic:
With a life history involving two free-living morphological phases.
Diplohaplontic:
With a life history involving an alternation between a haploid and diploid phase; these phases may be iso- or heteromorphic.
Diplont:
Alga in which the diploid phase is multicellular or dominant, with a cellular haploid phase represented by gametes.
Direct life history:
Reproduction of the same phase of the life history by means of asexual spores or propagules.
Distichous:
Arranged in two vertical rows along opposite sides of an axis.
Distromatic:
Two cell layers thick.
Edentate:
Lacking ‘teeth’ or tooth-like projections.
Endogenous:
Originating from within.
Endophytic:
Growing within the tissue of plants, but not necessarily parasitic.
Endozoic:
Growing within the tissue of animals, but not necessarily parasitic.
Epilithic:
Growing attached to rock (saxicolous).
Epiphytic:
Growing on plants or other algae.
Epizoic:
Growing on animals.
Evesiculate:
Without vesicles.
Excrescenses:
Outgrowths from the surface.
Falcate:
Sickle-shaped.
False hair:
Hair-like, tapering extensions of the filaments, with almost colourless cells, and without a basal meristem.
Fascicle:
A bundle-like cluster.
Fasciculate:
Resembling a fascicle.
Fenestrate:
Possessing window-like or pierced openings.
Filamentous:
Thread-like.
Filiform:
Thread-like; long and slender, and circular in cross-section.
Flabellate:
Having the shape of an open fan.
Flagelliform:
Whip-like; long, thin and tapering.
Flexouse::
Bending or twisting from side to side.
Flexuous:
Axes or branches with zig-zag development, usually with the alternate braches on each side.
Foliaceous or Foliose:
Flat and expanded, resembling a leaf.
Fusiform:
Elongated and tapering towards each end.
Gametangial::
Gamete-producing.
Gametophyte:
The haploid, gamete-producing phase of a life history.
Geniculate:
Bearing flexible (uncalcified) joints.
Globose:
Spherical in form.
Gonimoblast:
A filament developing from the fertilised carpogonium or auxiliary cell, which gives rise to the carposporangia.
Gonimolobe:
Element of a gonimoblast that develops from a single initial cell and gives rise to caroposporangia: usually several are formed sequentially in cystocarp.
Hamifera:
Hook-like organs or outgrowths.
Haplobiontic:
Having a life history with a single phase, which may be either haploid or diploid.
Haplont:
Alga in which the dominant phase is a haploid gametophyte followed by a unicellular diploid zygote.
Hapteron:
An organ or outgrowth of attachment.
Heteromorphic:
Having dissimilar morphological forms.
Heterotrichous:
Consisting of both prostate and erect filaments.
Holdfast:
A basal attachment organ.
Hypacroblastic:
Origin of laterals from cells below the apical cell, from either the full length of the parent cell (hemiblastic) or from a subdivision of the parent cell (meriblastic).
Hyphae:
Elongate filaments (e.g. in the medulla of kelps).
Hypobasal:
Below the basal cell layer (usually in crustose algae).
Hypogenous:
Developing or growing on a lower surface; in some red algae referring to a position below the procarp-bearing cell.
Indeterminate:
Unrestricted or unlimited growth or number of parts.
Indusium:
A cellular cover over the sporangia.
Intercalary:
Situated between the apex and the base, or between nodes.
Intergenicula:
The calcified segments of the articulated Rhodophyta.
Isodiametric:
With vertical and horizontal diameters equal.
Isogamous:
Having morphologically similar gametes.
Isomorphic:
Having morphologically similar plants.
Laciniate:
Fringed; torn into finger-like or lobed segments.
Lamina:
Blade.
Laminate:
Layered.
Lanceolate:
Long and narrow, tapering on both ends, with the broadcast part approximately one third the length from the base.
Lappet:
A flap or fold.
Lateral:
to the side of, or term used for a side-branch.
Lenticular:
Lens-shaped.
Ligulate:
Strap-shaped.
Locule:
A compartment of a reproductive organ.
Medulla:
The central region of a thallus, inside the cortex.
Meristem:
A region of the thallus where the cells are actively dividing.
Meristoderm:
A superficial layer of dividing cells covering the thalli of Laminariales.
Moniliform:
Resembling a string of beads.
Monoecious:
Having both male and female reproductive structures on the same individual.
Monopodial:
A mode of development where the main axis continues growth and stays dominant over the lateral axes: the successive lateral branches which are given off are smaller than the main axis.
Monosiphonous:
Having a single row of cells without cortication.
Monosporangium:
A sporangium which releases a single spore which may be uni- or multinucleate.
Monostromatic:
Composed of a single layer of cells.
Mucro:
A sharp tip.
Mucronate:
Abruptly terminating in a sharp point.
Multiaxial:
With a type of thallus construction that comprises numerous axial filaments.
Multiseriate:
More than one cell wide:.
Multistratose:
Composed of many layers.
Nemathecium:
Reproductive sorus, projecting somewhat from the surface.
Obpyriform:
Inverted pear-shaped.
Ocellate:
Possessing spots; in some algae referring to a dense cluster of apical branchlets.
Oogomy:
The union of a motile or non-motile male gamete with a large non-motile female gamete.
Oogonium:
The female gametangium in oogamous sexual reproduction.
Orbicular (Orbiculate):
Almost circular or spherical.
Orthostichous:
Arranged in a straight, vertical row.
Ostiole:
A pore-like opening in some reproductive organs.
Ovate:
With the outline of an egg, the broader part towards the base.
Ovoid:
Egg-like, the thickest part towards the base.
Palmate:
Fan-shaped; like an open hand.
Papilliform:
Resembling a nipple-like projection.
Paniculate:
Arranged as loose, irregularly clustered branches.
Paraphyses:
Sterile cells or filaments associated with reproductive organs.
Parasporangium:
A reproductive structure producing many spores, but not homologous with a tetrasporangium.
Parenchymatous:
Composed of solid, two or three-dimensional tissue, usually comprising thin-walled, isodiametric cells.
Parietal:
Occurring against the wall of a cell.
Parthenogenesis:
Production of an individual from a single, unfertilised gamete.
Pectinate:
Comb-shaped.
Pedicellate:
Having or supported by a small stalk.
Peltate:
A rounded lamina with a stalk arising from near the centre of its under-surface.
Percurrent:
Occurring along the entire length; extending from base to apex.
Periaxial:
Immediately surrounding the axis or axial cells (e.g. in Ceramiaceae).
Pericarp:
Distinct sterile structures surrounding carposporophyte.
Pericentral:
Immediately surrounding, and derived from, central cells (e.g. Rhodomelaceae).
Periclinal:
Parallel to the surface or circumference.
Phaeophycean:
hair: A uniseriate filament without plastids with a basal meristem (in the brown algae).
Pinnate:
Structures in two rows in opposite sides of an axis, like a feather.
Planoconvex:
Flat on one side with a bulging curvature on the other.
Plastid:
A body in the cytoplasm containing the photosynthetic pigments.
Plectenchymatous:
Consisting of more or less densely interwoven filaments.
Plurilocular:
With many chambers (or locules) each producing a spore or gamete.
Polysiphonous:
Having a number of longitudinal rows of cells surrounding and cut off from a central filament, giving rise to a many-siphoned appearance (see siphonaceous: mainly in the family Rhodomelaceae).
Polysporanguim:
A sporangium containing more than four spores.
Polystichously:
Arranged in many series or ranks.
Polystromatic:
With three or more layers of cells.
Procumbent:
Trailing along the substrate; prostrate.
Propagule:
A multicellular structure that functions in asexual (vegetative) reproduction.
Proximal:
Situated towards the point of attachment or base of the thallus.
Pseudohair:
Particularly thin or colourless tip of filament.
Pseudoparenchymatous:
Comprising a system or network of closely packed filaments having the appearance of parenchymatous tissue.
Pulvinate:
Cushion shaped; or having a convex surface.
Punctae:
Dots or marks on the thallus.
Pyriform:
Pear-shaped.
Radial:
Occurring uniformly around a central axis.
Ramuli:
Small or secondary branches.
Receptacle:
The swollen end of a branch bearing reproductive organs.
Rectilinear:
Arranged in straight rows.
Repent:
Creeping along the substrate; prostrate.
Reticulate:
Resembling or forming a network.
Rhizines:
Slender thick-walled filaments found in the medulla of certain members of the Gelidiales.
Rhizoid:
An attaching or absorptive structure made up of one to few undifferentiated cells.
Rhizomatous:
Having a root-like structure (rhizome) running along the substratum, giving rise to attachment structures below and free upright parts.
Rhomboid:
Having sides of equal length, but not a square.
Rugose: :
Having a rough, wrinkled or ridged surface.
Saxicolous:
Growing attached to rock.
Schizogenic:
cavity:
Hollowing of a thallus, caused by separation of the cells.
Secund:
Branching only on one side of an axis.
Serrate:
Having a notched or toothed appearance.
Sessile:
Attached directly, without a stalk or stipe.
Simple:
unbranched or undivided.
Siphonaceous:
Cells tubular, multinucleate, and with no cross walls.
Sorus:
A dense cluster of sporangia or gametangia.
Spermatia:
Non-motile male gametes in the division Rhodophyta.
Spiniform:
Spine-like.
Sporangia:
Spore-producing cells or structures.
Sporangial:
Pertaining to asexual spore production.
Sporophyll:
A fertile, spore-producing blade.
Sporophyte:
The diploid, spore-producing phase of a life history.
Stellate:
Star-shaped.
Stephanokant:
With a crown of flagella.
Stichidium:
A specialised branch containing tetrasporangia or spermatangia (in the Rhodophyta).
Stipitate:
Borne on a short stalk termed a stipe.
Stolon:
A horizontal stem-like structure which gives rise to upright parts at various intervals.
Subdichotomous:
Tending towards or mostly dichotomous.
Sublittoral:
fringe:
The upper portion of the sublittoral zone occasionally uncovered by extreme low tide.
Subtidal:
That region which is always submerged; usually only applies to the inshore areas.
Supralittoral:
The area above the spring high water mark, or the ‘splash’ or ‘spray’ zone.
Sympodial:
growth:
A mode of development where the main axis is continually replaced by lateral axes i.e. with each branching the lateral takes over from the then ‘main’ axis.
Terete:
Cylindrical and circular in cross-section.
Tetrahedral:
Having four plane faces at approximately 109.5° apart; in tetrasporangia, dividing into four three-sided pyramids, the apices meeting in the centre.
Tetrasporangium:
A sporangium found in red algae and Dictyotales of the brown algae, containing four spores.
Thallus:
The relatively simple body of a plant (in this case a seaweed).
Tortuous:
Twisted.
Torulose:
Cylindrical, but with bulges or contractions at intervals.
Trichoblast:
A laterally-produced, colourless, simple or branched filament found in algae belonging to the family Rhodomelaceae, also associated with reproductive structures in that group.
Trichogyne:
A hair-like structure or extension of the female gametangium which intercepts the male gametes (Rhodophyta).
Trichothallic:
Growth (in the Phaeophyta) in which the site of cell division is at the base of a filament or groups of filaments.
Truncate:
Appearing to be cut off at the top; ended abruptly as if cut off.
Tubercle:
a small, rounded, wart-like protuberance.
Turf:
A dense layer of tightly-packed upright plants.
Umbilicate:
Having depressions resembling navels or dimples, often associated with holdfasts.
Undulate:
Having wavy margins.
Uniaxial:
Having a single central axis or filament.
Unilocular:
With a single chamber (or locule).
Uniseriate:
Consisting of a single series or row.
Unistratose:
Consisting of a single layer of cells.
Urceolate:
Urn-shaped.
Utricle:
A filament or tube which is dilated or swollen at its end or apex.
Verrucose:
Covered with warts or wart-like projections.
Verticillate:
Bearing successive whorls of three or more branches/branchlets per node.
Vesicular (Vesiculate):
Having the form of a vesicle i.e. a small bladder-like sac.
Zonate:
Having a pattern of meiotic cell division where the spores are cut off in three parallel planes, giving a stacked appearance (in tetrasporangia); divided into zones.
Zooid:
A motile flagellate reproductive cell, gamete or spore.
Zooidangium:
A zooid-producing structure.
Zoosporangium:
A sporangium producing asexual motile flagellate spores.

 

This glossary is reproduced from Stegenga et al. (1997).

Citing this publication:

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 23 September 2018