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). |
costule |
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STRUCTURE |
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A longitudinal primary vein in a diminutive laminar structure, such as the blade of a leaflet, pinna or pinnule; a diminutive costa (rib). |
torus 2 pl. tori |
= receptacle |
STRUCTURE |
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The short, expanded, compound axial structure surmounting a peduncle and basal to two or more flowers, or to the florets of a capitulum (head) in Asteraceae (Compositae), where it may bear paleae (receptacular bracts), scales, bristles, trichomes, or subulate enations, and may be smooth or variously pitted (alveolate, foveolate). |
rachilla 1 var. rhachilla |
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STRUCTURE |
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A second- or higher-order axis of a compound leaf blade, bearing higher-order rachillae, leaflets, pinnules and/or tendrils. |
plumule |
= epicotyl |
STRUCTURE |
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A distinguishable nascent shoot developed in the embryo in some taxa, consisting of a shoot axis with unexpanded internodes and one or more leaf primordia, being that portion of the embryo above the level of cotyledon insertion; the primordial shoot, when developed by the embryo within a seed; the first bud of a spermatophyte, when developed by an embryo within the seed. In other taxa the shoot is represented in the embryo only by a quiescent apical meristem at the summit of the embryonic axis. |
thallus 1 pl. thalli |
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STRUCTURE |
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The vegetative portion of a shoot when not differentiated into stem and leaves; esp. in Lemnaceae. |
sorus pl. sori |
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STRUCTURE |
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A cluster of sporangia borne upon a fertile frond, usually on its abaxial surface; often covered during maturation by a protective membrane, the indusium, that is an outgrowth from the epidermis; in Polypodiophyta. |
ligule 1 |
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STRUCTURE |
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A strap-shaped enation from or distal portion of a structure. |
rostrum 2 pl. rostra |
= beak |
STRUCTURE |
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The inner, horn-like segment of a coronal lobe; esp. in Asclepiadaceae. |
horn |
= corniculum |
STRUCTURE |
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A straight or curved, slenderly conic or conoidal protrusion or terminal portion that resembles an animal horn. |
dyad |
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STRUCTURE |
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A pair of coherent pollen grains shed as a unit. |
bractlet 2 |
= bracteole, prophyll(um); < bract |
STRUCTURE |
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A second- or higher-order bract within, and subtending some portion of, an aggregate branching structure, especially when subtending a flower. |
tuft |
> coma |
STRUCTURE |
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A distinct, compact, relatively dense, homogeneous aggregation of plants or constituent structures such as stems, branches, leaves, bracts or trichomes. |
enation |
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STRUCTURE |
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A relatively small outgrowth from an otherwise regular boundary or surface of a larger structure. |
rhizome |
= rootstock |
STRUCTURE |
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An underground, usually horizontal stem, often superficially resembling a root but easily distinguished by the presence of nodes, from which it branches exogenously to produce the aboveground portion(s) of the shoot. |
sawtoothlet |
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STRUCTURE |
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A diminutive sawtooth. See also scallop (crena), scalloplet (crenule), tooth (dens), toothlet. |
basal cell |
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STRUCTURE |
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Any of the ring of cells forming the lowermost (proximal) portion of an antheridial wall. |
squamule 1 |
= squamella; < scale |
STRUCTURE |
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A diminutive squama (lepis). |
midrib |
= midnerve, midvein; < costa, nerve, rib, vein |
STRUCTURE |
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A primary vein that runs longitudinally through the center of a leaf or other basically laminar structure. See also lateral vein, secondary vein, tertiary vein, veinlet. |
prickle |
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STRUCTURE |
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Any unvascularized spine-like enation originating in the epidermis, cortex, or mesophyll of any shoot part. See also spine, thorn. |
aril 1 (broad sense) |
> arillode, arillus |
STRUCTURE |
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An appendicular structure that wholly or partly envelops a seed and is produced from or a modification of the funicle, raphe, outer integument, or (in some Pinophyta) a subtending involucre; usually fleshy or pulpy, sometimes spongy or tufted-capillate, often brightly colored. |
haustorium pl. haustoria |
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STRUCTURE |
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An absorbing and anchoring organ, often root-like, excrescent from a vegetative part of a parasitic or hemiparasitic plant, by which the plant communicates intimately with and derives sustenance and support from its host plant, into whose tissues the haustorium intrudes. |
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. |
nerve |
= vein; > 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. |
shoot 1 |
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STRUCTURE |
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Collectively, all those portions of a plant body that are anatomically distinct from the root, the component axes differentiated into nodes and internodes, and branching exogenously from the former. |