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). |
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. |
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. |
annulus 2 pl. annuli |
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STRUCTURE |
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A row of protruding specialized sporangial wall cells that extends upward from the base of the sporangium and over its apex, thus forming an incomplete circumferential ring; esp. in Polypodiophyta. The inner and radial walls of the annular cells are markedly thickened and the structure functions as a spore-releasing and -disseminating mechanism as a result of differential stresses developed within the mature sporangial wall upon desiccation. |
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. |
primocane |
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STRUCTURE |
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A biennial or perennial stem before it has begun flowering, when the latter does not occur until at least its second season of growth; esp. in Rubus (Rosaceae). |
exocarp |
= epicarp |
STRUCTURE |
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The outermost tissue layer of a pericarp. |
epicotyl |
= plumule |
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. |
gynandrium pl. gynandria |
= column, gynostemium |
STRUCTURE |
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A central floral structure consisting of the partly to wholly fused (connate and adnate) androecium and gynoecium; esp. in Orchidaceae. |
ocrea pl. ocreae var. ochrea |
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STRUCTURE |
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A tubular sheath that encircles a stem at a node, subtending a petiole; thought to have arisen evolutionarily by lateral fusion of two stipules; in Polygonaceae. |
pyrene 2 |
= stone |
STRUCTURE |
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The hard seed of a drupelet; esp. in Rosaceae. |
microsporangium pl. microsporangia |
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STRUCTURE |
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A sporangium that produces microspores. |
velum pl. vela |
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STRUCTURE |
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A membranous adaxial flap or fold of vegetative tissue wholly or partly covering the sporangial cavity of a sporophyll; in Isoëtaceae. |
adventitious root |
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STRUCTURE |
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A root that arises laterally from some part of a shoot, often from the lower portion of a main stem. |
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). |
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. |
perisperm |
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STRUCTURE / SUBSTANCE |
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A genetically diploid (2n chromosomes) nutritive tissue in a seed; containing stored carbohydrate and/or oil utilized by the embryo prior to and especially upon germination; derived from the nucellus. See also endosperm (albumen). |
endosperm |
= albumen |
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. |
vestiture |
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STRUCTURE / SUBSTANCE |
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See vesture. |
indument |
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STRUCTURE / SUBSTANCE |
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See indumentum. |
vesture var. vestiture |
= indumentum |
STRUCTURE / SUBSTANCE |
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The trichomes and/or exuded substance that overlie a surface proper, regarded collectively. See also coating, pubescence. |
indumentum pl. indumenta var. indument |
= vesture |
STRUCTURE / SUBSTANCE |
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The trichomes and/or exuded substance that overlie a surface proper, regarded collectively. See also coating, pubescence. |
resin |
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SUBSTANCE |
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A substance of high molecular weight consisting of organic acids, esters, and/or terpenes, produced within plant tissue and exuded from wounds as a liquid that hardens to an amorphous glassy state upon exposure. |
latex pl. latices, latexes |
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SUBSTANCE |
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A moderately viscous and sticky exudate, often milky, sometimes otherwise colored or clear. Overlaps conceptually with gum. |