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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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collar 1 |
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STRUCTURE |
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The free portion (if any) of a floral tube, distal to its casing and/or neck when one or both is/are present. |
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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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cane |
< culm, stem |
STRUCTURE |
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A woody, aboveground culm. Use of this term or culm instead of stem is a matter of tradition and preference, not of descriptive precision or necessity. |
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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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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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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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chalaza pl. chalazae, chalazas |
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STRUCTURE |
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The basal (proximal) portion of an ovule, adjacent to its junction with the funiculus. |
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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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sorus pl. sori |
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STRUCTURE |
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A cluster of sporangia borne upon a fertile frond, usually on its abaxial surface; often covered during maturation by a protective membrane, the indusium, that is an outgrowth from the epidermis; in Polypodiophyta. |
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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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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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pith |
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STRUCTURE |
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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. |
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casing |
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STRUCTURE |
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The portion (if any) of a floral tube that is adnate to the gynoecium. See also collar, neck. |
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torus 2 pl. tori |
= receptacle |
STRUCTURE |
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The short, expanded, compound axial structure surmounting a peduncle and basal to two or more flowers, or to the florets of a capitulum (head) in Asteraceae (Compositae), where it may bear paleae (receptacular bracts), scales, bristles, trichomes, or subulate enations, and may be smooth or variously pitted (alveolate, foveolate). |
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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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petiole |
< stalk, stipe (broad sense, not recommended) |
STRUCTURE |
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The stalk, when present, of a leaf. |
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barbel |
= barbella |
STRUCTURE |
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A small barb. |
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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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cladophyll |
= cladode, phylloclade |
STRUCTURE |
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A stem segment that functions as a leaf; often more or less compressed. |
