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wood |
= xylem |
STRUCTURE |
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The water-conducting and usually main supporting tissue of a plant or portion thereof, characterized by the presence of tracheary elements (tracheids and sometimes vessel elements); the lignified tissue of a plant or component structure, composed almost entirely of secondary tissue, i.e., that derived by secondary or lateral growth from a cambium in structures a season or more old. As commonly used, the term wood generally refers only to secondary xylem, which constitutes the bulk of a mature woody stem, but it properly refers also to primary xylem, wherever found. See also sapwood, heartwood. |
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megasporangium pl. megasporangia |
= macrosporangium (not recommended) |
STRUCTURE |
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A sporangium that produces megaspores. |
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barbellule |
= barbellula |
STRUCTURE |
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A small barbel (barbella); a very diminutive barb. |
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nectary |
< gland |
STRUCTURE |
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A multicellular, anatomically distinct structure that produces and exudes nectar. |
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velum pl. vela |
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STRUCTURE |
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A membranous adaxial flap or fold of vegetative tissue wholly or partly covering the sporangial cavity of a sporophyll; in Isoëtaceae. |
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ear |
= auricle |
STRUCTURE |
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A small, rounded, lateral lobe at the base of a laminar structure, lying in more or less the same plane as the remainder of the lamina. |
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fringe |
= fimbria |
STRUCTURE |
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A marginal series or cycle of regular, slender, closely adjacent, more or less flexible segments or protrusions, when treated as an aggregate structure. |
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connective |
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STRUCTURE |
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The tissue between and joining the laterally opposed thecae of an anther, connecting them with the distal end of the staminal filament when the latter is present. |
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floret |
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STRUCTURE |
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A very small, structurally specialized flower, especially when occurring in capitulum (head; Asteraceae), or in a spikelet (Poaceae), where it includes the immediately subtending bracts (lemma and palea). |
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septum pl. septa |
> dissepiment, replum, trabecula |
STRUCTURE |
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A topologically and/or texturally distinct wall or partition that separates chambers or locules within an ovary, fruit or sporangium. |
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ala 1 pl. alae |
= wing |
STRUCTURE |
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Any elongate, relatively thin protrusion or appendage. |
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ochrea |
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STRUCTURE |
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See ocrea. |
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cilium 1 pl. cilia |
> capillus, hair; >< trichome |
STRUCTURE |
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A hair-like trichome or other surficial process. |
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megaspore |
= macrospore (not recommended) |
STRUCTURE |
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A female spore; a spore of the larger of two types produced by the sporophytes of a heterosporous taxon; produced in a megasporangium; giving rise upon germination to a megagametophyte. |
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sterigma pl. sterigmata |
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STRUCTURE |
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A portion of a lamina that is prolonged and adherent to the supporting axis beneath the point of vascular insertion. |
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leaf 1 pl. leaves |
= frond, macrophyll (not recommended), megaphyll; > frond, needle |
STRUCTURE |
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A principal, vegetative shoot organ borne laterally from a stem node; its vascular tissues, if any, continuous with those of the stem; undergoing no significant secondary growth; usually more or less bilaterally symmetrical; comprising a distal, usually laminar blade and/or a proximal stalk (petiole) or sheath; usually a primary site of photosynthesis. |
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pseudopetiole |
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STRUCTURE |
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A distinctly constricted, more or less stalk-like, proximal portion of a leaf, evolutionarily derived from the blade, the original petiole reduced to the point of absence or vestigiality; esp. in Poaceae (Gramineae). |
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crista pl. cristae |
= crest |
STRUCTURE |
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A laterally elongate, relatively thin, irregular or notched, apical protrusion. |
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bark |
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STRUCTURE |
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The outermost portion of any shoot or root axis having secondary growth, consisting of all those tissues outside the vascular cambium; sometimes exhibiting zonation into inner, living bark and outer, dead bark; usually described only as to external appearance. |
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needle |
< leaf, macrophyll (not recommended), megaphyll |
STRUCTURE |
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A relatively stiff, compressed-acerose leaf; in Pinophyta. |
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filament |
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STRUCTURE |
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The stalk, when present, of a stamen, clearly differentiated from and bearing at its summit an anther. |
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pinna pl. pinnae |
< leaflet |
STRUCTURE |
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One of the first-order divisions or leaflets of a pinnate frond; in Polypodiophyta. See also pinnule. |
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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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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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areola 1 pl. areolae |
= areole |
STRUCTURE |
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Any distinctive surficial discontinuity of generally circular outline, whether concave, flush, or convex; when protuberant, sometimes bearing trichomes or spines, as in some Cactaceae. This term is used only when such entities are deemed structurally distinctive enough to merit description in their own rights, rather than as aspects of the surface. |
