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. |
dyad |
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STRUCTURE |
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A pair of coherent pollen grains shed as a unit. |
albumen |
= endosperm |
STRUCTURE / SUBSTANCE |
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A genetically triploid (3n chromosomes) nutritive tissue in a seed; containing stored carbohydrate and/or oil utilized by the embryo prior to and especially upon germination; derived from fusion of the two polar nuclei (n + n chromosomes) of the embryo sac with a sperm nucleus from the pollen tube (n chromosomes). See also perisperm. |
knot-shaped |
= gongylodate, gongyloid, knob-shaped, nodiform |
solid shape |
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Approximately globose, the surface convoluted or not, like a knob or knot; usually applied only to structures or components that are relatively small. |
hispid |
= setose; < bristly |
pubescence |
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Bearing relatively long and slender, more or less straight, terete, fine-pointed, stiff trichomes. See also hispidulous (setulose, small-bristly). |
S-shaped 1 |
= sigmoid |
course |
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Curved more or less regularly first in one direction and then in the opposite direction, like the letter S. |
lobe |
? division, segment |
STRUCTURE |
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Any generally convex, major peripheral protrusion or component sector that is delimited by concavities in the surface or margin and that is not proximally distinct from the remainder of the whole. |
mucous 1 |
= mucilaginous; < glutinous |
coating |
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Of a slimy substance, or becoming so upon wetting. |
biconvex 1 |
= lens-shaped, lenticular |
plane shape |
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Elongate, narrow, broadest at the middle, attenuate to acute ends, the sides convex; like the outline of a double-convex lens viewed from its edge. |
squamellose |
< scaly |
pubescence |
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Finely squamose (lepidote). |
wedge-shaped 2 |
= cuneate, obtriangular |
plane shape |
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Inversely triangular; like the outline of the broad lateral face of a wedge, broadest at the apex. See also obdeltate. |
phyllode |
= phyllodium |
STRUCTURE |
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A leaf deemed to consist entirely or almost entirely of tissues evolutionarily derived from the petiole, all or a distal portion of which has become expanded and blade-like, the original blade reduced to the point of absence or vestigiality. |
pubescence |
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CHARACTER |
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Collective aspect of trichomes borne on the surface. Many of the terms traditionally used for describing pubescence have been defined and used in so many differing and often contradictory ways that they have become hopelessly ambiguous. This is attributable mainly to overdefinition within this portion of the traditional lexicon — that is, to highly arbitrary and widely variant restriction of a term's scope to some one detailed combination of trichome character states (shape, size, orientation, etc.). By derivation these are essentially general terms, really suited only for denoting overall aspect. The diversity actually encountered in nature defies comprehensive and unambiguous resolution into any limited suite of precisely specified, mutually exclusive, complex character states that can be associated with these terms, which are best used only in their general senses. Sometimes, such description will be sufficient in itself; more often, additionally or alternatively, the various attributes of the individual trichomes should be described. This is the only strategy that allows for full description of any possible condition, including the presence of more than one type of trichome. The various terms used for describing pubescence have never been semantically consistent; in some cases they refer to the trichomes themselves, while in others they apply to the bearing surface or structure; e.g., sericeous (the trichomes themselves are collectively silky) versus barbate (the structure is bearded). See also coating, indumentum (vesture). |
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. |
erose 1 |
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margin |
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Having rough, very irregular depressions throughout. |
canescent |
= hoary |
pubescence |
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Densely covered with gray, fine, relatively short, capillate trichomes. |
trunk |
= bole; < main stem, primary stem |
STRUCTURE |
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The relatively stout, columnar, main stem of a distinct aboveground portion of a tree. |
rostrum 2 pl. rostra |
= beak |
STRUCTURE |
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The inner, horn-like segment of a coronal lobe; esp. in Asclepiadaceae. |
planoconvex |
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solid shape |
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Relatively thin with opposite broad faces, one plane and one convex. |
induplicate |
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aestivation |
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Basically valvate but with each member involute, the lateral abaxial surfaces of adjacent members contiguous. |
auriform |
= ear-shaped |
solid shape |
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Resembling a mammalian outer ear. |
divaricate |
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arrangement |
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Strongly divergent. |
acropetal |
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development |
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Proceeding toward the apex, thus more advanced basally or proximally than apically or distally within a given frame of reference. |
helical 2 |
= spiral |
course |
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Curving with regularly increasing radius from one end to the other in one general plane. |
micropyle |
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FEATURE |
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The small pore in the integuments of an ovule at its apex, through which the pollen tube grows; or the corresponding aperture or scar in the coat of the seed that develops subsequently. |