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membrane |
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STRUCTURE |
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A relatively thin layer of tissue that covers or separates other, different tissue(s) and/or empty space(s). |
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perianth |
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STRUCTURE |
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Collectively, all the sterile, primary, lateral organs (tepals, or sepals and/or petals) of a flower; inserted upon the floral axis immediately beneath (proximal to) the reproductive organs (androecium and/or gynoecium) and surrounding them, often protectively; lacking in some taxa; the individual members typically laminar and more or less foliaceous; widely regarded as consisting of the evolutionarily modified leaves of a fertile shoot; the constituent members undifferentiated with respect to one another, or else differentiated into more or less distinct floral envelopes (calyx and corolla), one or the other of which is deemed lacking in some taxa due to evolutionary reduction following differentiation. |
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tooth pl. teeth |
= dens |
STRUCTURE |
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One of a series of regularly spaced, angular, marginal convexities oriented more or less perpendicular to the generalized perimeter of a laminar structure. See also sawtooth, sawtoothlet, scallop (crena), scalloplet (crenule), toothlet. |
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vasculature |
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STRUCTURE |
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The vascular strands of all orders (veins and veinlets) in a particular part or organ, regarded collectively; consisting of conducting tissues (xylem, phloem) and associated supporting and enclosing tissues (e.g., sclerenchyma, collenchyma). |
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mamilla pl. mamillae |
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STRUCTURE |
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A nipple- or teat-shaped protrusion. |
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bristle 1 |
= arista, awn, seta |
STRUCTURE |
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A slender, more or less straight and stiff, fine-pointed, terminal or subterminal appendage or prolongation, sometimes a continuation of the bearing structure's central primary vein, as on a glume, lemma, or palea in Poaceae (Gramineae). |
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nucellus pl. nucelli |
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STRUCTURE |
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The distinct, genetically diploid tissue layer immediately surrounding the embryo sac of an ovule; often considered equivalent to a megasporangium wall. |
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blade |
= lamina |
STRUCTURE |
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The expanded, more or less planate, distal portion, when present, of a leaf, leaflet or bract. |
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neck (archegonial) |
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STRUCTURE |
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The distal narrowed portion of an archegonium above its bulbous base. |
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dyad |
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STRUCTURE |
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A pair of coherent pollen grains shed as a unit. |
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gemma pl. gemmae |
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STRUCTURE |
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A vegetative propagule by which a gametophyte reproduces asexually; produced by a process analogous to budding, from a more or less cupulate specialized area (gemmae cup) on the surface of the plant body (thallus); in Psilotophyta, Lycopodiophyta, Equisetophyta, Polypodiophyta. |
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knee 2 |
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STRUCTURE |
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An emergent portion of an otherwise normally submerged secondary root of a wetland tree, resembling a bent human knee. |
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perianth tube |
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STRUCTURE |
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A relatively narrow, fully connate portion of a syntepalous (gamotepalous) perianth proximal to a broader portion (limb) that comprises the distinct or connate distal portions of the tepals. |
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prop root |
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STRUCTURE |
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A relatively stout adventitious root arising from the lower portion of a main stem and extending outward and downward toward the substrate, within which it ultimately becomes anchored, thus buttressing the aboveground portion of the plant. |
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rhizoid |
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STRUCTURE |
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Any structure that is similar to a root in appearance and function but that is not a true root ontogenetically and anatomically, especially one produced from a gametophyte thallus. |
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subsidiary cell |
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STRUCTURE |
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One of the cytologically distinctive epidermal cells that are sometimes present in a stomate and that surround and are regularly oriented in relation to the guard cells. |
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bristle 2 |
= seta; > glochid, glochidium; < trichome |
STRUCTURE |
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A trichome that is elongate, more or less straight, terete, fine-pointed, and stiff. |
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testa pl. testae |
= seed coat |
STRUCTURE |
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The outer protective layer of a seed, developed from the ovular integument(s). |
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neck (floral tube) |
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STRUCTURE |
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The solid, usually constricted portion of a floral tube sometimes present between casing and collar when those are both present. |
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cell 1 |
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STRUCTURE |
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Any of the basic structural/functional units that collectively or individually make up the various tissues of a plant; comprising, at least while physiologically active, a nucleus with included genetic material (chromosomes), a surrounding cytoplasm with included organelles (e.g., ribosomes, mitochondria, plastids), an enclosing membrane, and an exterior cellulosic wall. |
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dens pl. dentes |
= tooth |
STRUCTURE |
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One of a series of regularly spaced, angular, marginal convexities oriented more or less perpendicular to the generalized perimeter of a laminar structure. See also crena (scallop), crenule (scalloplet), sawtooth, sawtoothlet, toothlet. |
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endocarp |
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STRUCTURE |
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The innermost tissue layer of a pericarp. |
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sapwood |
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STRUCTURE |
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That portion of the wood (xylem) of a stem or root whose cells are still living and functional; concentric about the heartwood once the latter has begun to form. |
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stigma pl. stigmata, stigmas |
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STRUCTURE |
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An exposed, localized portion of a pistil that retains deposited pollen and stimulates its germination, the pollen tubes then growing through or along it toward the ovule(s). |
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hypogynium pl. hypogynia |
= gynophore; < stalk, stipe (broad sense, not recommended) |
STRUCTURE |
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The basal portion of an ovary when constricted and stalk-like above the level of perianth insertion, bearing the main body of the pistil at its summit; in Cyperaceae. |
