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coma pl. comae, comas |
< tuft |
STRUCTURE |
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A prominent single tuft of relatively long and slender, flexible, capillate trichomes; esp. from a seed, as in Asclepias (Asclepiadaceae). |
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palet 2 |
= pale, palea |
STRUCTURE |
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The upper or distal of the (usually) two distinctive bracts immediately subtending the flower in a grass (Poaceae) spikelet. |
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carina 2 pl. carinae |
= keel |
STRUCTURE |
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Collectively, the two relatively small, connate or coherent, abaxial (lower) petals that form the keel-like portion of a papilionaceous corolla. |
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embryo |
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STRUCTURE |
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The rudimentary spermatophyte contained within a viable seed. |
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neck (archegonial) |
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STRUCTURE |
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The distal narrowed portion of an archegonium above its bulbous base. |
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hypogynium pl. hypogynia |
= gynophore; < stalk, stipe (broad sense, not recommended) |
STRUCTURE |
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The basal portion of an ovary when constricted and stalk-like above the level of perianth insertion, bearing the main body of the pistil at its summit; in Cyperaceae. |
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beak 1 |
= rostrum |
STRUCTURE |
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A relatively long, tapering, more or less rigid and pointed enation or termination. |
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prickle |
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STRUCTURE |
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Any unvascularized spine-like enation originating in the epidermis, cortex, or mesophyll of any shoot part. See also spine, thorn. |
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antheridium pl. antheridia |
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STRUCTURE |
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A male gametangium; a multicellular fertile organ of a mature gametophyte within which male gametes (antherozoids, spermatozoids) are produced and from which they are discharged, in some taxa forcibly, through a pore. Technically present but highly reduced and of no descriptive significance in Magnoliophyta and part of Pinophyta. |
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trophophyll |
= sterile frond |
STRUCTURE |
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A frond that does not bear sporangia; in Polypodiophyta. See also fertile frond. |
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stomate |
= stomatal apparatus, stoma (broad sense) |
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. |
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mesocarp |
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STRUCTURE |
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The middle tissue layer of the pericarp of a fruit. |
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vasculature |
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STRUCTURE |
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The vascular strands of all orders (veins and veinlets) in a particular part or organ, regarded collectively; consisting of conducting tissues (xylem, phloem) and associated supporting and enclosing tissues (e.g., sclerenchyma, collenchyma). |
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torus 1 pl. tori |
= receptacle |
STRUCTURE |
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The relatively short, simple, axial structure surmounting a pedicel and basal to the flower, usually broader than the pedicel. |
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embryo sac |
< megagametophyte |
STRUCTURE |
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The multinucleate generative cell of an ovule, within which fertilization and zygote formation occur; resulting from meiotic division of a megaspore mother cell within the nucellus, and thus genetically haploid; its contents generally considered to represent an evolutionarily reduced gametophyte. |
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neck (floral tube) |
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STRUCTURE |
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The solid, usually constricted portion of a floral tube sometimes present between casing and collar when those are both present. |
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cotyledon |
= seed leaf |
STRUCTURE |
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Any of the one or more primary foliar structures of an embryonic seed plant, proximal to all succeeding leaf primordia; sometimes serving as a storage organ for food reserves in the seed, as in peas and beans. |
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petiole |
< stalk, stipe (broad sense, not recommended) |
STRUCTURE |
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The stalk, when present, of a leaf. |
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thallus 1 pl. thalli |
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STRUCTURE |
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The vegetative portion of a shoot when not differentiated into stem and leaves; esp. in Lemnaceae. |
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operculum pl. opercula |
= lid |
STRUCTURE |
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A distal, cover-like portion of a structure whose main body is otherwise closed, transversely discontinuous with the main body around most of the circumference, or becoming partially or wholly separate by transverse dehiscence; as of an ascidium (pitcher), pollen grain, pyxis, or sporangium (spore case). |
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beak 2 |
= rostrum |
STRUCTURE |
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The inner, horn-like segment of a coronal lobe; esp. in Asclepiadaceae. |
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twig |
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STRUCTURE |
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The terminal portion of an ultimate branch of a woody stem, representing the most recent increment of growth and bearing or having borne the current or most recent increment of leaves. See also branchlet. |
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seta 1 pl. setae |
= arista, awn, bristle |
STRUCTURE |
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A slender, more or less straight and stiff, fine-pointed, terminal or subterminal appendage or prolongation, sometimes a continuation of the bearing structure's central primary vein, as on a glume, lemma, or palea in Poaceae (Gramineae). |
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dyad |
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STRUCTURE |
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A pair of coherent pollen grains shed as a unit. |
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axis pl. axes |
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STRUCTURE |
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Any unitary and longitudinally continuous structure that bears laterally the subordinate portion(s), if any, of a plant root or shoot or any subdivision thereof and that represents the main line of structural development and/or symmetry distal to its origin, irrespective of the particular ontogenetic growth pattern involved. See also primary axis. |
