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rhizoid |
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STRUCTURE |
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Any structure that is similar to a root in appearance and function but that is not a true root ontogenetically and anatomically, especially one produced from a gametophyte thallus. |
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subsidiary 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. |
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bristle 2 |
= seta; > glochid, glochidium; < trichome |
STRUCTURE |
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A trichome that is elongate, more or less straight, terete, fine-pointed, and stiff. |
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testa pl. testae |
= seed coat |
STRUCTURE |
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The outer protective layer of a seed, developed from the ovular integument(s). |
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neck (floral tube) |
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STRUCTURE |
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The solid, usually constricted portion of a floral tube sometimes present between casing and collar when those are both present. |
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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. |
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dens pl. dentes |
= tooth |
STRUCTURE |
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One of a series of regularly spaced, angular, marginal convexities oriented more or less perpendicular to the generalized perimeter of a laminar structure. See also crena (scallop), crenule (scalloplet), sawtooth, sawtoothlet, toothlet. |
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endocarp |
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STRUCTURE |
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The innermost tissue layer of a pericarp. |
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sapwood |
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STRUCTURE |
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That portion of the wood (xylem) of a stem or root whose cells are still living and functional; concentric about the heartwood once the latter has begun to form. |
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stigma pl. stigmata, stigmas |
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STRUCTURE |
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An exposed, localized portion of a pistil that retains deposited pollen and stimulates its germination, the pollen tubes then growing through or along it toward the ovule(s). |
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hypogynium pl. hypogynia |
= gynophore; < stalk, stipe (broad sense, not recommended) |
STRUCTURE |
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The basal portion of an ovary when constricted and stalk-like above the level of perianth insertion, bearing the main body of the pistil at its summit; in Cyperaceae. |
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turion |
< sucker |
STRUCTURE |
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A scaly sucker. |
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rostrum 1 pl. rostra |
= beak |
STRUCTURE |
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A relatively long, tapering, more or less rigid and pointed enation or termination. |
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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. |
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pericarp |
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STRUCTURE |
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The portion of a fruit wall that is derived from the ovary wall; consisting of three more or less distinct tissue layers (exocarp or epicarp, mesocarp, and endocarp) that may or may not differ greatly in structure and/or function; the wall of a fruit, excluding any tissues of extra-ovarian (accessory) origin. |
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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. |
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mamma pl. mammae |
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STRUCTURE |
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A rounded-conoidal protrusion, resembling the breast of a mammal. |
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lenticel |
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STRUCTURE |
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A specialized, anatomically distinct structure within the periderm of a stem, consisting of comparatively spongy, sometimes suberized tissue distinct from others of the periderm; extending radially through the periderm and visible as a circular to elongate discontinuity in the color, texture, and/or relief of the outer surface of the stem; serving as a conduit for gas exchange between the stem interior and the atmosphere. |
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cycle |
= series, verticil, whorl |
STRUCTURE |
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A set of three or more lateral structures that are inserted around an axis at the same level. |
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ear |
= auricle |
STRUCTURE |
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A small, rounded, lateral lobe at the base of a laminar structure, lying in more or less the same plane as the remainder of the lamina. |
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rostrum 2 pl. rostra |
= beak |
STRUCTURE |
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The inner, horn-like segment of a coronal lobe; esp. in Asclepiadaceae. |
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mentum pl. menta |
= column foot |
STRUCTURE |
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A lateral, often nectariferous protrusion from the proximal portion of a column, opposite the labellum, projecting in front of the rest of the flower; in Orchidaceae. |
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cross-vein |
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STRUCTURE |
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A relatively short, secondary or higher-order vein that runs directly between two veins of the next lower order, intersecting them more or less perpendicularly. |
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prophyll(um) pl. prophylls, prophylla |
= bracteole, bractlet; < 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. |
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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. |
