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 05 October 2024