accessory cell |
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STRUCTURE |
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One of the cytologically distinctive epidermal cells that are sometimes present in a stomate and that surround and are regularly oriented in relation to the guard cells. |
inflorescence 2 |
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STRUCTURE |
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The basic architectural unit of the flower-producing portion of a plant; comprising one or more flowers, their associated supporting axes (peduncles, main axes, branches and pedicels), if any, and the appendages thereto (bracts, bractlets or bracteoles or prophylls, involucres, involucels, and glumes), if any; delimited by the insertion or gradation of a single peduncle, peduncle cluster, pedicel, pedicel cluster, or sessile flower, as the case may be, directly upon or into some proximal vegetative structure not of one of these types; depending upon the type(s) of flowers included, may be bisexual (all flowers bisexual), staminate (all flowers staminate), pistillate (all flowers pistillate), sterile (all flowers sterile), or mixed (two or more types of flowers present); most appropriately described using nominative terms. |
barb 1 |
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STRUCTURE |
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Any relatively short, stiff, sharp, acutely inserted or bent, antrorse or retrorse, terminal or lateral appendage. |
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. |
needle |
< leaf, macrophyll (not recommended), megaphyll |
STRUCTURE |
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A relatively stiff, compressed-acerose leaf; in Pinophyta. |
phyllary |
= involucral bract; < bract (broad sense) |
STRUCTURE |
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One of the bracts composing the involucre of a capitulum (head); in Asteraceae (Compositae). |
bud scale |
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STRUCTURE |
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A scale that, alone or aggregated with others, envelops and protects a bud. |
primary vein |
> costa, midnerve (not recommended), midrib, midvein, rib; >< lateral vein |
STRUCTURE |
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A strand belonging to the first order of vasculature in a leaf or other basically laminar structure. See also secondary vein, tertiary vein, veinlet. |
knee root |
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STRUCTURE |
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A specialized secondary root of a wetland tree, a portion of which projects above mean water level and appears to bend as a leg does at the knee, its distalmost portion being anchored in the substrate beneath the water. The knee of the root is commonly regarded as a conduit for gas exchange between root interior and atmosphere, a function whose need is posited on the basis of the highly anaerobic and saturated conditions prevailing in wetland substrates. |
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). |
viscidium pl. viscidia |
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STRUCTURE |
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A small, viscid, glandular body of rostellar origin that becomes connected with a pollinium caudicle, either directly or through an intervening stipe, by which the pollinium attaches to a pollinating insect; in Orchidaceae. |
gynaecium |
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STRUCTURE |
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See gynoecium. |
pollinarium pl. pollinaria |
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STRUCTURE |
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A pollinium together with, when present, its stipe and viscidium; the entire unit of pollinium dispersal. |
carina 2 pl. carinae |
= keel |
STRUCTURE |
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Collectively, the two relatively small, connate or coherent, abaxial (lower) petals that form the keel-like portion of a papilionaceous corolla. |
ochrea |
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STRUCTURE |
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See ocrea. |
pyrene 1 |
= stone |
STRUCTURE |
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The hard inner portion of a drupe, consisting of osseous endocarp and included seed. |
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. |
velamen pl. velamina |
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STRUCTURE |
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A thin, often chartaceous (papery, papyraceous) or pergamentaceous (parchment-like), outermost tissue layer of an aerial root; esp. in Orchidaceae. |
involucral bract |
= phyllary; < bract (broad sense) |
STRUCTURE |
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One of the bracts composing the involucre of a capitulum (head,); in Asteraceae (Compositae). |
translator arm |
= caudicle |
STRUCTURE |
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An attenuate end portion by which a pollinium adheres to a pollinating insect, either directly or by means of a terminal viscidium, the latter, when present, sometimes attached by an intervening stipe; esp. in Asclepiadaceae, Orchidaceae. |
barb 2 |
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STRUCTURE |
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A trichome terminated by one or two small, relatively short, stiff, sharp, acutely reflexed appendages. |
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. |
phylloclade |
= cladode, cladophyll |
STRUCTURE |
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A stem segment that functions as a leaf; often more or less compressed. |
thorn |
= spine |
STRUCTURE |
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Any sharp, stiff, simple or branched, woody appendage having vascular tissues confluent with those of the bearing structure. "Spine" is often preferred when the appendage is homologous with a leaf or stipule, and "thorn" when it is homologous with a branch. See also prickle. |
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. |