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mesochilium |
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STRUCTURE |
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The central portion of a labellum (lip) that has distinct proximal, distal, and central parts; in Orchidaceae. See also epichilium, hypochilium. |
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convolute 2 |
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arrangement |
cotyledons |
Each rolled or folded inward longitudinally, one enveloping the other. |
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perigynium 2 pl. perigynia |
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STRUCTURE |
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A phyllary (involucral bract) or palea (pale, palet) that fully encloses a cypsela; in Asteraceae (Compositae). |
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versatile |
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fixation |
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Attached in a manner allowing free rotation and declination. |
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irregular 1 |
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architecture |
perianth, calyx, corolla |
Imperfectly actinomorphic, the constituents disposed symmetrically but unequal in size and/or shape. See also peloric. |
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repand |
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margin |
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Gently or shallowly sinuate. |
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annulus 2 pl. annuli |
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STRUCTURE |
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A row of protruding specialized sporangial wall cells that extends upward from the base of the sporangium and over its apex, thus forming an incomplete circumferential ring; esp. in Polypodiophyta. The inner and radial walls of the annular cells are markedly thickened and the structure functions as a spore-releasing and -disseminating mechanism as a result of differential stresses developed within the mature sporangial wall upon desiccation. |
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spicule |
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STRUCTURE |
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A small, fine, stiff, acute protrusion that resembles a little spike. |
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ribbed 2 |
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solid shape |
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Having two or more prominent, elongate, relatively narrow, essentially parallel protrusions that extend over all or most of its length or circumference. |
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apotropous |
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orientation |
ovule |
Anatropous but the whole recurved such that the raphe (adnate portion of the funiculus) faces the ovary wall (placenta) and the ovule is parallel to it, the micropyle facing the free basal portion of the funiculus. |
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gum |
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SUBSTANCE |
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A highly viscous and sticky exudate that becomes more or less elastic and/or deformably solid upon drying. Overlaps conceptually with latex. |
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sporophyte |
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PLANT |
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The main, ultimate, spore-bearing stage in the diploid (2n chromosomes) phase of a taxon's life cycle. Two morphologically and genetically distinct and alternate phases together constitute the complete life cycle in sexually reproducing taxa, the other phase (gametophytic) being haploid (n chromosomes). Any taxon whose life cycle is confined to one or the other phase is limited to asexual means of reproduction, since sexual reproduction with consequent genetic recombination is impossible without alternation between haploid and diploid states via meiosis and fertilization. The term sporophytic applies to any part of the diploid phase, including all unicellular to multicellular entities belonging to it, whereas sporophyte is reserved for the principal and directly spore-producing stage of that phase. |
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latrorse |
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dehiscence |
anther |
Opening laterally, on the tangential sides. See also extrorse, introrse. |
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face |
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FEATURE |
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A relatively large, flat or shallowly curved portion of the external surface of a three-dimensional structure, bounded by more or less distinct topological discontinuities. |
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obcordate |
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plane shape |
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Inversely cordate (heart-shaped). |
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poricidal |
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dehiscence |
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Forming one or more apertures in the exterior wall, usually apically or sub-apically, through which the contents pass to the outside. |
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staminate |
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architecture |
inflorescence, flower, floret |
Having functional stamens but no functional pistils, thus unisexual and male. |
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cilium 2 pl. cilia |
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STRUCTURE |
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A motile hair- or whip-like structure extending from the surface of a cell. |
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ocrea pl. ocreae var. ochrea |
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STRUCTURE |
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A tubular sheath that encircles a stem at a node, subtending a petiole; thought to have arisen evolutionarily by lateral fusion of two stipules; in Polygonaceae. |
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axillary |
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insertion |
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Within the axil; nodal and at or very close to the vertex of the distal angle between a lateral structure, especially a leaf, and the axis that bears it. |
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determinate |
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development |
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Having the terminal (central, apical, or distal) portion differentiating first and the lateral (peripheral, basal, or proximal) portions later, development thus proceeding sequentially downward or outward, growth of the whole thereby organizationally limited. |
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ovary |
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STRUCTURE |
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The proximal portion of a pistil (either simple or compound) within which the ovules are borne; usually of somewhat greater diameter and/or volume than the remainder of the pistil. |
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horizontal |
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orientation |
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Parallel to the horizon, perpendicular to the force of gravity. |
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diplotegium pl. diplotegia |
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nominative |
fruit |
A pyxis with accessory tissue adnate to the pericarp; derived from an inferior ovary. |
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loculicidal |
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dehiscence |
fruit |
Splitting longitudinally through the outer wall(s) and directly into the locule(s), between the sutures, if any. |
