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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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spathe |
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STRUCTURE |
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A usually relatively large, sometimes showy, foliose bract subtending and sometimes partially enclosing an inflorescence, esp. a spadicate one; in Liliidae (monocotyledons). |
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cap cell |
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STRUCTURE |
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The single cell, or one of the several cells, forming the uppermost (distal) portion of an antheridial wall. |
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epiphyllous |
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position |
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Upon the leaves, or partially adnate thereto and apparently arising therefrom. |
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naked 1 |
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architecture |
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Lacking a covering that might have been expected. |
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rhipidiate |
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architecture |
inflorescence |
Comprising one or more rhipidia. |
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winter annual |
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nominative |
plant |
Annual, germinating in autumn, overwintering in a vegetative state (usually as a rosette aboveground), reproducing sexually from early spring through summer, and dying promptly thereafter. See also summer annual. |
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catadromous |
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venation |
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Having the first lateral vein in each pinna or primary segment of the frond arise from its midvein on the side toward the base of the frond, the pinnule or secondary segment that it leads to often disproportionately larger than the next distal ones. |
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non-porous |
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porosity |
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Lacking vessels, the tracheary elements limited to tracheids and, sometimes, fiber-tracheids. |
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non-septate |
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architecture |
trichome |
Lacking transverse inter- or intracellular septa or partitions. |
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arillate |
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architecture |
seed |
Having an aril. |
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cuspidate |
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apex |
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Tapering gradually to a rigid tip composed of both vascular and laminar tissues. |
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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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polyadal |
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arrangement |
pollen |
Shed in groups of more than four, each group comprising grains from two or more original tetrads, the latter intact or not. |
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channel |
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FEATURE |
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A longitudinal, transversely rounded depression; esp. along the adaxial surface of a petiole or petiolule. |
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sap |
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SUBSTANCE |
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Generally, the fluid content of a plant body; more precisely, the sugary fluid transported by the phloem. |
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deliquescent 2 |
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texture |
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Delicately fleshy and liquifying at maturity or with pressure; e.g., petals of Tradescantia (Commelinaceae). |
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prolate |
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plane shape |
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Symmetrically elongate parallel to the developmental or polar axis. |
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fixed |
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fixation |
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Attached to the bearing structure in a manner allowing no significant rotation or declination in relation to it. |
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opaque |
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coloration |
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Not transmitting light. |
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scarious |
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texture |
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Very thin, dry, and not green. |
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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. |
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stilt-rooted |
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architecture |
plant |
Bearing and partly supported by stilt roots. |
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hypogynous |
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insertion |
perianth, calyx, corolla, androecium |
Entirely free from the gynoecium or any floral cup, arising from a level proximal or lateral to the base of the gynoecium. See also epigynous, perigynous. |
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strobiloid |
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architecture |
flower |
Characterized by a general lack of adnation among the different sets of basic floral structures, any significant degree of fusion limited to connation within sets, thus with ovary(ies) superior and lacking a floral tube. |
