prophyll(um) pl. prophylls, prophylla |
= bracteole, bractlet; < bract |
STRUCTURE |
|
A second- or higher-order bract within, and subtending some portion of, an aggregate branching structure, especially when subtending a flower. |
flange |
|
STRUCTURE |
|
A relatively broad, circumferential rim or ridge that protrudes laterally. |
palet 2 |
= pale, palea |
STRUCTURE |
|
The upper or distal of the (usually) two distinctive bracts immediately subtending the flower in a grass (Poaceae) spikelet. |
pith |
|
STRUCTURE |
|
The central ground tissue of a stem or, when present, of a root, consisting of thin-walled parenchyma cells; distinct and more or less soft and spongy relative to the other tissues of the axis; sometimes partly or wholly degenerating after secondary growth has begun. |
costule |
|
STRUCTURE |
|
A longitudinal primary vein in a diminutive laminar structure, such as the blade of a leaflet, pinna or pinnule; a diminutive costa (rib). |
floricane |
|
STRUCTURE |
|
A biennial or perennial stem after it has begun flowering, when that does not occur until at least its second season of growth; applied especially to the stems of brambles (Rubus spp.). |
microphyll |
|
STRUCTURE |
|
A small, lateral, leaf-like enation that, evolutionarily, is not a true leaf, i.e., whose vasculature, if any, consists of only a single median strand not ontogenetically integral with the vasculature of the bearing stem and not associated with leaf gaps in the stele of the stem; in Bryophyta, Psilotophyta, Lycopodiophyta, Equisetophyta. |
arillode |
< aril (broad sense) |
STRUCTURE |
|
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. |
petiole |
< stalk, stipe (broad sense, not recommended) |
STRUCTURE |
|
The stalk, when present, of a leaf. |
knee root |
|
STRUCTURE |
|
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. |
shoot 2 |
|
STRUCTURE |
|
A vascularized axis that is differentiated into nodes and internodes and that branches exogenously from the former, together with any non-axial structures borne from it. |
sterile frond |
= trophophyll |
STRUCTURE |
|
A frond that does not bear sporangia; in Polypodiophyta. See also fertile frond. |
enation |
|
STRUCTURE |
|
A relatively small outgrowth from an otherwise regular boundary or surface of a larger structure. |
bracteole 2 |
= bractlet, prophyll(um); < bract |
STRUCTURE |
|
A second- or higher-order bract within, and subtending some portion of, an aggregate branching structure, especially when subtending a flower. |
spore |
|
STRUCTURE |
|
A simple, usually unicellular, sometimes oligocellular propagule derived by meiotic division of a diploid (2n chromosomes) sporocyte within a sporangium, thus of haploid (n chromosomes) genetic constitution. A spore constitutes the first ontogenetic stage of a gametophytic generation and gives rise to a usually multicellular gametophyte upon germination. Though technically present in seed-bearing plants, by itself it is descriptively significant only in those taxa that do not produce seeds. |
spore body |
= sporocarp |
STRUCTURE |
|
A multicellular structure that bears and more or less encloses several to (usually) many sporangia, the latter often aggregated into sori within it See also megasporocarp (macrosporocarp, not recommended), microsporocarp. |
massula pl. massulae |
|
STRUCTURE |
|
A body of coherent pollen grains, dispersed as a unit; esp. in Asclepiadaceae, Orchidaceae. |
lenticel |
|
STRUCTURE |
|
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. |
frond |
< leaf, macrophyll (not recommended), megaphyll |
STRUCTURE |
|
A leaf in Polypodiophyta or Palmae (Arecaceae), usually relatively large and often highly dissected. Use of this term in preference to "leaf" in descriptions of ferns and palms is a matter of tradition only, not of morphological or evolutionary distinction. |
rib |
= costa; > midnerve (not recommended), midrib, midvein; >< lateral vein |
STRUCTURE |
|
A primary vein of a laminar structure, having a longitudinal course, either medial or lateral, often prominent. See also secondary vein, tertiary vein, veinlet. |
husk |
|
STRUCTURE |
|
A more or less dry, hard or fibrous, simple or compound enclosure or outer layer of a seed, fruit or inflorescence. |
arillus pl. arilli |
= aril (strict sense); < aril (broad sense) |
STRUCTURE |
|
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. |
limb 1 |
|
STRUCTURE |
|
A relatively broad portion of a syntepalous (gamotepalous) perianth, synsepalous (gamosepalous) calyx, or sympetalous (gamopetalous) corolla distal to a narrower tube, spreading outward or ascending from the tube, comprising the distinct or connate distal portions of the tepals, sepals, or petals; except in bisexual or staminate disc florets of Asteraceae (Compositae). |
plantlet |
|
STRUCTURE |
|
A juvenile, complete plant produced asexually by budding, as from the leaf margin in some Kalanchoë (Crassulaceae); this term is usually applied only while such vegetatively produced offspring remain attached to the plant of origin. |
toothlet |
|
STRUCTURE |
|
A diminutive tooth (dens). See also sawtooth, sawtoothlet, scallop (crena), scalloplet (crenule). |