antheridium (pl. antheridia): a structure that produces motile male gametes (sperm).
ascoglossan: referring to the order Ascoglossa (=Sacoglossa), an order of sea slugs (Mollusca).
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.
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.
gametangium (pl. gametangia): a structure that produces gametes.
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.
gastropoda: A class of Mollusks including snails slugs and limpets.
haploid: having a single set of chromosomes - half the normal number (1n).
herbivory: feeding on plants.
heteromorphic: more than one kind of form.
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.
saxicolous: 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.
