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  FHL Marine Botany  ::::::::::::::::::::::::::::::   Species List | Student List | Glossary ::::::::::::::::::::Other FHL Courses

Abaxial – on the surface facing away from the main axis of the plant; turned toward base.

Adaxial – on the surface facing the main axis of the plant.

Alginic acid – a viscous gum that is abundant in the cell walls of brown algae.

Antheridia – (singular: antheridium) reproductive structures on male gametophytes that produce motile male gametes.

Apical meristem –a meristem (region of rapid growth) at the apex of a branch or stem.

Apomeiotic – formed without meiosis.

Achene – a fruit with a single seed that does not adhere to, and can be easily separated from, the interior wall of the fruit.

Auxiliary cell – cell on female gametophyte from which the diploid gonimoblast begins to develop.

Bullate – pocketed, puckered, or blistered appearance.

Carpogonial branches – in red algae, branches of female gametophytes that bear carpogonia, the female sex cells which house eggs. When fertilized, carpogonia remain on the female plant and develop into carposporophytes.

Carposporangium – (plural: carposporangia) in red algae, the cell in a carposporophyte that produces carpospores.  

Carpospore – a non-motile, usually diploid spore of red algae produced by the carposporophyte that in most red algae develops into a free-living tetrasporophyte.

Carposporophyte – formed by the union of haploid gametes in red algae; diploid (2n) stage of the life cycle that is carried by the haploid female gametophyte in the cystocarp; produces carpospores.

Climax community – the set of organisms that establish over time if the ecosystem is undisturbed and achieves an equilibrium state.

Conceptacle – structure housing the reproductive tissues.

Cortex –tissue external to the central medulla and internal to the epidermis.

Corticated – possessing a cortex.

Cystocarp – the reproductive structure on the blade surface of female gametophytes; composed of the carposporophyte and surrounding female gametophyte tissue.

Determinate growth– growth that is limited/comes to an end.

Dichotomously branched – branching in a Y-shaped pattern.

Dioecious two houses; sexes are separate; male and female gametes come from separate plants.

Diplohaplontic – a life cycle that encompasses a diploid and haploid phase.

Epilithic – growing on rock.

Epiphytic – growing on other algae.

Frond – a single erect, often leaf-like part of a thallus that can support several blades, as in Egregia or Macrocystis.

Gametophyte – an alga in the haploid (1n) phase of the life cycle that produces gametes by mitosis; in red algae, tetraspores develop into gametophytes.

Genicula – decalcified flexible regions of coralline algal thallus.

Gland cells – cells that have the ability to excrete hormones and/or enzymes.

Gonimoblast – filaments of carposporophyte arising from the fertilized carpogonium.

Haptera – root-like structures of a kelp holdfast, 1-10 mm in diameter.

Heteromorphic –having a different morphology during haploid and diploid phases.

Holdfast – the base of the plant that attaches the stipe to the substrate.

Homosporous producing only one kind of spore.

Hydrophilous – pollinated by water.

Hypotonic – having the lower osmotic pressure of two solutions.

Indeterminate growth– continuous growth.

Inflorescent – flowering; bearing reproductive structures.

Intercalary meristematic growth – growth occurs in a defined region, usually near the base of the blade.

Intergenicula– calcified stiff regions of coralline algal thallus.

Intertidal – the region of shore that is submerged during high tides and exposed to air during low tides.

Involucral filaments – a bunch of sterile branches below a cystocarp and commonly arching over it.

Isomorphic – having the same morphology during both haploid and diploid phases.

Lacunae – pits or cavities.

Laminarin – high molecular weight secondary photosynthate, a food storage polysaccharide in the Phaeophyceae composed principally of B-1, 3 linked glucans containing 16 to 31 glucose residues; laminarin occurs as an oil-like liquid outside of the chloroplasts in a vesicle surrounding the pyrenoid.

Lamoxirene – an order-specific sexual pheromone released by female gametophyte in brown algae.

Lanceolate – narrow, lance-shaped.

Leptomorph – a thin, elongated type of rhizome.

Mannitol – a white, crystalline, water-soluble, slightly sweet alcohol, C6H8(OH)6, used as a dietary supplement and dietetic sweetener and in medical tests of renal function.

Marine Botany – study of the coolest and most beautiful organisms in the ocean.

Medulla – the cell layer in the center of an algal thallus.

Monoecious one house; an individual has both male and female reproductive structures.

Mucilage ducts – intercellular spaces in cortex of stipe and blade of some Laminariales lined by secretory cells that produce and secrete fucoidin.

Oblong – a shape that longer than it is broad, elliptical.

Oogamy – when large, non-motile female gametes are fertilized by small, motile male gametes.

Parenchymatous – composed of parenchyma, a tissue of thin-walled cells of similar diameters.

Perennial – having a life cycle more than two years, recurring.

Phototrophs – organisms that capture the energy in sunlight and use it for metabolism; photosynthesizers.

Pit Connections – holes in the septa between adjacent red algal cells, a unique and distinctive feature of red algae. Called primary when between related red algal cells, often filled with 'plug' of former intracellular debris (a pit plug). Called secondary when between unrelated red algal cells; allow transfer of nutrients and cell contents between neighboring cells.

Plasmodesmata – microscopic channels traversing the cell walls of plant cells allowing for transport between them.

Plurangium – a multi-compartmented (plurilocular) reproductive structure that produces gametes by mitosis.

Pneumatocyst – a large air filled bladder or float

Pyrenoid – proteinaceous area of the chloroplast associated with the formation of photosynthates.

Rachis – the tough flattened tissue in the center region of the frond to which the blades and pneumatocysts are attached in Egregia menziesii.

Saxicolous – growing on rock.

Sieve Elements –structures found in the Laminariales andFucales used in translocation of sugars from mature areas to areas growing rapidly; consist of longitudinal files of cells with perforated sieve plates on their end walls; found between the cortex and medulla.

Spermatangium – (plural: spermatangia) a cell on a gametophyte that produce a single non-motile male gamete.

Sporophyte – alga in diploid (2n) phase of the life cycle that produces spores by meiosis.

Sori – (singular: sorus) reproductive regions on the thallus.

Stipe – stem-like region between blade and holdfast.

Sublittoral zone – zone beyond the low tidewater mark (that is always submerged) that receives enough light to support rooted vegetation.

Subtidal – the region of shore that is below the mean low water mark for spring tides; almost always submerged.

Terminal lamina – in Egregia menziesii, the relatively short meristematic region at the distal end of the frond. It originates from the rachis and is wider than the rachis.

Tetrasporangium – (plural: tetrasporangia) a spore generating structure in the tetrasporophyte phase of a red alga life cycle that produces four haploid spores.

Tetraspore – one of four haploid spores produced meiotically in a tetrasporangium in red algae that develops into a gametophyte.

Tetrasporophyte – red alga in free-living, diploid stage of the life cycle that produces tetraspores by meiosis; carpospores develop into tetrasporophytes.

Thallus – (plural: thalli) the body of an alga.

Triphasic – life history cycle with three life stages.

Trumpet hyphae – drawn-out sieve cells, wider at the cross-walls than in the middle of the cells; trumpet cells form a network of connecting cells in the pith which transport photosynthates through the blade.

Unangium – (a.ka. unilocular sporangium, plural: unangia) an enlarged, single-compartment reproductive structure that undergoes meiosis and then mitosis to produce many haploid (1n) zoospores.

Zoospores – motile spores with flagella.