series |
= cycle, 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. |
joint |
= articulation |
STRUCTURE |
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A distinct, relatively narrow zone of demarcation between adjacent main portions of an elongate structure, often thicker than the rest of the structure and sometimes a site of eventual abscission. |
ligule 1 |
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STRUCTURE |
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A strap-shaped enation from or distal portion of a structure. |
rostrum 2 pl. rostra |
= beak |
STRUCTURE |
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The inner, horn-like segment of a coronal lobe; esp. in Asclepiadaceae. |
stoma 1 (broad sense) pl. stomata |
= stomatal apparatus, stomate |
STRUCTURE |
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A localized functional epidermal unit consisting of a microscopic pore and two encircling specialized cells, the guard cells, which, through changes of turgor pressure in response to environmental conditions, regulate the size of the pore and thus the rates of transpiration and gas exchange through it; the whole surrounded or not by associated, cytologically distinctive epidermal cells, the subsidiary or accessory cells, which, when present, are regularly oriented in relation to it. |
paraphysis pl. paraphyses |
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STRUCTURE |
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An elongate, multicellular, sterile structure borne between sporangia within a sorus; in Polypodiophyta. |
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. |
columella 2 pl. columellae, columellas |
= carpophore; < stalk |
STRUCTURE |
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The stalk supporting a mericarp after dehiscence of a schizocarpic fruit, the central axis of the fruit having split longitudinally to yield two or four such stalks; composed of receptacular and (primarily) gynoecial tissues; esp. in Apiaceae (Umbelliferae). |
palea 2 pl. paleae, paleas |
= pale, palet |
STRUCTURE |
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The distal bract of the (usually) two that immediately subtend the flower in a grass (Poaceae) spikelet; the other is the lemma. |
unguis pl. ungues |
= claw |
STRUCTURE |
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The abruptly much narrower proximal portion, when present, of a laminar structure, esp. a petal; of variable shape itself, but usually attenuate toward the base. |
costa pl. costae |
= rib; > midnerve (not recommended), midrib, midvein; >< lateral vein |
STRUCTURE |
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A primary vein of a laminar structure, having a longitudinal course, either medial or lateral, often prominent. See also secondary vein, tertiary vein, veinlet. |
appendage |
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STRUCTURE |
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Any subordinate structure ontogenetically derived from and associated with a given organ or part. |
lamella pl. lamellae |
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STRUCTURE |
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A thin layer of tissue that forms a plate within tissue of lesser density or between areas of empty space. |
tetrad |
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STRUCTURE |
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A group of four pollen grains originating from a single pollen mother cell. |
squamella 1 pl. squamellae |
= squamule; < scale, trichome |
STRUCTURE |
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A diminutive squama (lepis). |
radicle |
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STRUCTURE |
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The primary root, or its primordium, in an embryo; the portion of an embryo axis that develops into the root. |
vexillum pl. vexilla |
= banner, standard |
STRUCTURE |
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The relatively large, erect adaxial (upper) petal in a papilionaceous corolla. |
ligule 2 |
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STRUCTURE |
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An adaxial, distal enation from a leaf sheath, especially in most grasses (Poaceae) and sedges (Cyperaceae); usually unitary and membranous, sometimes instead consisting of a row of ciliate processes. See also hastula. |
valve |
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STRUCTURE |
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Any longitudinal segment of a fruit wall delimited by lines of dehiscence. |
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. |
rhizophore |
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STRUCTURE |
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A stem branch that bears no leaves and from which roots eventually arise; esp. in Selaginellaceae. |
staminodium pl. staminodia |
= staminode |
STRUCTURE |
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Any sterile structure deemed to represent a modified stamen, homology being inferred on the basis of structural similarity, ontogeny, and/or position; sometimes petaloid, sometimes nectariferous, sometimes connate with others or adnate to other floral structures. |
pitcher |
= ascidium, pitcher blade |
STRUCTURE |
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A pitcher-shaped (ascidiform) leaf blade, sometimes lidded (operculate), usually carnivorous; esp. in Nepenthaceae, Sarraceniaceae. |
column 1 |
= gynandrium, 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. |
fimbria pl. fimbriae |
= fringe |
STRUCTURE |
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A marginal series or cycle of regular, slender, closely adjacent, more or less flexible divisions or protrusions, when treated as an aggregate structure. |