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crozier |
= fiddlehead |
STRUCTURE |
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A circinate leaf (frond) prior to full expansion, while still wholly or distally coiled; esp. in Polypodiophyta. |
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squamule 2 |
= squamella; < scale |
STRUCTURE |
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A small, dry bract borne on the compound receptacle (torus) of a capitulum (head); in Asteraceae (Compositae). |
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sterigma pl. sterigmata |
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STRUCTURE |
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A portion of a lamina that is prolonged and adherent to the supporting axis beneath the point of vascular insertion. |
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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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corniculum pl. cornicula |
= horn |
STRUCTURE |
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A straight or curved, slenderly conic or conoidal protrusion or terminal portion that resembles an animal horn. |
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ray floret |
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STRUCTURE |
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A floret that has a zygomorphic corolla, is pistillate (either fertile or sterile) or neuter, and is borne in a radiate capitulum (head) peripheral (proximal) to the disc florets; in Asteraceae (Compositae). |
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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). |
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epidermal cell |
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STRUCTURE |
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Any of the unspecialized cells of an epidermis; i.e., any other than stomatal guard cells or cells directly associated with trichomes. While the latter specialized cells are also properly epidermal cells, they are treated separately for descriptive purposes and, for the sake of convenience, use of the general term is restricted to the unspecialized cells that constitute the bulk of an epidermis. |
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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. |
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filament |
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STRUCTURE |
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The stalk, when present, of a stamen, clearly differentiated from and bearing at its summit an anther. |
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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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aril 2 (strict sense) |
= arillus |
STRUCTURE |
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An appendicular structure that wholly or partly envelops a seed and is an outgrowth from the funicle or raphe, and thus is ontogenetically derived from the placenta; usually fleshy or pulpy, sometimes spongy or tufted-capillate, often brightly colored. |
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spadix pl. spadices |
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STRUCTURE |
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A thick, fleshy, primary inflorescence axis bearing sessile flowers more or less sunken into its surface, the whole subtended and sometimes partially enclosed by a specialized bract, the spathe; esp. in Araceae. |
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megasporophyll |
= macrosporophyll (not recommended); > carpel, cone scale, ovuliferous scale |
STRUCTURE |
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A sporophyll that bears only megasporangia and, in Pinophyta, naked ovules that develop subsequently. |
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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. |
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carpel |
< macrosporophyll (not recommended), megasporophyll, pistil |
STRUCTURE |
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A more or less abstract unit of floral structure conceptually equivalent to a simple pistil or its putative evolutionary precursor (megasporophyll) or derivative (constituent of compound pistil); often regarded as the basic evolutionary unit of the gynoecium. |
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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). |
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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. |
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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. |
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indument |
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STRUCTURE / SUBSTANCE |
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See indumentum. |
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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. |
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vestiture |
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STRUCTURE / SUBSTANCE |
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See vesture. |
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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. |
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viscin |
= elastoviscin |
SUBSTANCE |
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A sticky, elastic material, especially that forming the threads that sometimes connect pollen grains. |
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gum |
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SUBSTANCE |
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A highly viscous and sticky exudate that becomes more or less elastic and/or deformably solid upon drying. Overlaps conceptually with latex. |
