sheath (leaf) |
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STRUCTURE |
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The lower (basal or proximal), fundamentally laminar but strongly involute portion of one of the non-petiolate leaves characteristic of most monocotyledons (Liliidae); distinct from the leaf blade, which, when present, is borne distally upon it; analogous, though not necessarily homologous, with a petiole; usually more or less completely enclosing a portion of the stem above the node from which the leaf is borne. |
pale 2 |
= palea, palet |
STRUCTURE |
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The upper or distal of the (usually) two distinctive bracts immediately subtending the flower in a grass (Poaceae) spikelet. |
flange |
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STRUCTURE |
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A relatively broad, circumferential rim or ridge that protrudes laterally. |
pistillode |
= pistillodium |
STRUCTURE |
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Any sterile structure deemed to represent a modified pistil, homology being inferred on the basis of structural similarity, ontogeny, and/or position; sometimes nectariferous, sometimes connate with others or adnate to other floral structures. |
sepal |
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STRUCTURE |
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One of the one or more constituent members of a calyx; usually green and leaf-like, but sometimes with color and/or texture otherwise, sometimes petaloid; may be distinct or else connate with one or more others and/or may be free or else adnate to one or more other floral structures. |
heartwood |
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STRUCTURE |
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The senescent inner or central portion of the wood (xylem) of an older stem or root, its cells no longer living, in which conduction has ceased and primary reserve materials are no longer stored; often containing terminal metabolic products; usually darker in color than the living, conducting sapwood that encircles it. |
spicule |
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STRUCTURE |
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A small, fine, stiff, acute protrusion that resembles a little spike. |
corolla pl. corollae, corollas |
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STRUCTURE |
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Collectively, the petals of a flower, whether distinct or connate; the inner or distal envelope of a differentiated perianth, whether the other envelope (calyx) is actually present or is deemed to be absent due to evolutionary reduction. |
coma pl. comae, comas |
< tuft |
STRUCTURE |
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A prominent single tuft of relatively long and slender, flexible, capillate trichomes; esp. from a seed, as in Asclepias (Asclepiadaceae). |
petal |
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STRUCTURE |
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One of the one or more constituent members of a corolla; colored and showy in many taxa, inconspicuous in size and/or color in others; may be distinct or else connate with one or more others, and/or may be free or else adnate to one or more other floral structures. |
dyad |
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STRUCTURE |
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A pair of coherent pollen grains shed as a unit. |
rhachilla |
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STRUCTURE |
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See rachilla. |
nodule |
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STRUCTURE |
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A small nodiform (gongylodate, gongyloid, knob-shaped, knot-shaped) segment or protrusion; esp. in roots of Fabaceae (Leguminosae) and harboring nitrogen-fixing bacteria. |
arillode |
< aril (broad sense) |
STRUCTURE |
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A "false" aril; an appendicular structure that wholly or partly envelops a seed and is produced from or a modification of the outer integument or (in some Pinophyta) a subtending involucre, but not from the funicle or raphe, and thus is not ontogenetically derived from the placenta; usually fleshy or pulpy, sometimes spongy or tufted-capillate, often brightly colored. |
megasporophyll |
= macrosporophyll (not recommended); > carpel, cone scale, ovuliferous scale |
STRUCTURE |
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A sporophyll that bears only megasporangia and, in Pinophyta, naked ovules that develop subsequently. |
ray floret |
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STRUCTURE |
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A floret that has a zygomorphic corolla, is pistillate (either fertile or sterile) or neuter, and is borne in a radiate capitulum (head) peripheral (proximal) to the disc florets; in Asteraceae (Compositae). |
apiculum 1 pl. apicula |
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STRUCTURE |
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A short, slender, angular tip that is not notably harder or stiffer than the main body of the bearing structure. See also mucro. |
receptacle 1 |
= torus |
STRUCTURE |
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The relatively short, simple, axial structure surmounting a pedicel and basal to the flower, usually broader than the pedicel. |
palea 1 pl. paleae, paleas |
= pale, palet, receptacular bract |
STRUCTURE |
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A small papery (chartaceous) to membranous bract borne on the compound receptacle (torus) of a capitulum (head) in Asteraceae (Compositae). |
pistillodium pl. pistillodia |
= pistillode |
STRUCTURE |
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Any sterile structure deemed to represent a modified pistil, homology being inferred on the basis of structural similarity, ontogeny, and/or position; sometimes nectariferous, sometimes connate with others or adnate to other floral structures. |
calyculus 1 pl. calyculi |
= epicalyx |
STRUCTURE |
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A whorl of bracts immediately subtending (beneath or outside) a calyx; literally, a little calyx. |
corolla tube 1 |
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STRUCTURE |
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A relatively narrow, fully connate portion of a sympetalous (gamopetalous) corolla proximal to a broader portion (limb) that comprises the distinct or connate distal portions of the petals; except in bisexual or staminate disc florets of Asteraceae (Compositae). |
indusium pl. indusia |
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STRUCTURE |
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A protective membrane that is an outgrowth from the epidermis and covers a sorus during its maturation; in Polypodiophyta. |
rhachis |
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STRUCTURE |
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See rachis. |
vein |
= nerve; > costa, midnerve, midrib, midvein, rib |
STRUCTURE |
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A strand belonging to any except the ultimate (least in diameter) order of vasculature in a leaf or other foliaceous structure. See also lateral vein, primary vein, secondary vein, tertiary vein, veinlet. |