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. |
sporocarp |
= spore body |
STRUCTURE |
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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. |
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. |
cladode |
= cladophyll, phylloclade |
STRUCTURE |
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A stem segment that functions as a leaf; often more or less compressed. |
rachis 1 var. rhachis |
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STRUCTURE |
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A main or first-order axis of a compound leaf blade. |
lepis pl. lepides |
= squama; < scale, trichome |
STRUCTURE |
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A relatively thick, planate trichome. See also squamella. |
dyad |
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STRUCTURE |
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A pair of coherent pollen grains shed as a unit. |
appendage |
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STRUCTURE |
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Any subordinate structure ontogenetically derived from and associated with a given organ or part. |
articulation |
= joint |
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. |
fibrous root |
< diffuse root |
STRUCTURE |
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A diffuse root that includes a significant component of woody or sclerotic strands and is consequently tough and often wiry. |
subsidiary cell |
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STRUCTURE |
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One of the cytologically distinctive epidermal cells that are sometimes present in a stomate and that surround and are regularly oriented in relation to the guard cells. |
main stem |
= primary stem; > bole, trunk |
STRUCTURE |
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The one, or any of the more than one, first-order stem(s), or first-order portion(s) of the collective stem, of a shoot. |
short-shoot |
= spur |
STRUCTURE |
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A first- or higher-order woody stem branch having relatively unelongated internodes, thus proximate nodes, and limited duration of growth, usually branching little if at all; often a main locus of flower production; usually more or less perpendicular to the axis that bears it and resembling a spur projecting from it; sometimes becoming more or less spinose after elongation ceases; esp. in Rosaceae. |
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. |
receptacular bract |
= pale, palea, palet |
STRUCTURE |
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A small papery (chartaceous) to membranous bract borne on the compound receptacle (torus) of a capitulum (head) in Asteraceae (Compositae). |
embryotega pl. embryotegae, embryotegas |
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STRUCTURE |
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A small, hardened, lid-like portion of the testa (seed coat) at the micropyle of some seeds, detaching at germination. |
haft |
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STRUCTURE |
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The narrow portion of a structure that is notably constricted. |
sporophyll |
= spore leaf; > fertile frond |
STRUCTURE |
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A leaf or homologous structure that bears sporangia. See also megasporophyll (macrosporophyll, not recommended), microsporophyll. |
strobilus pl. strobili |
= cone; > female cone, macrostrobilus (not recommended), male cone, megastrobilus, microstrobilus |
STRUCTURE |
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A compound or complex reproductive structure consisting of a central axis bearing congested sporophylls and sometimes other lateral members (e.g., bracts) that are sterile. |
rachis 2 var. rhachis |
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STRUCTURE |
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A main or first-order axis of an inflorescence. |
verticil |
= cycle, series, whorl |
STRUCTURE |
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A set of three or more lateral structures that are inserted around an axis at the same level. |
plantlet |
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STRUCTURE |
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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. |
megaphyll |
= leaf, macrophyll (not recommended); > frond, needle |
STRUCTURE |
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A principal, vegetative shoot organ borne laterally from a stem node; its vascular tissues, if any, continuous with those of the stem; undergoing no significant secondary growth; usually more or less bilaterally symmetrical; comprising a distal, usually laminar blade and/or a proximal stalk (petiole) or sheath; usually a primary site of photosynthesis. |
seed |
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STRUCTURE |
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A mature or ripened ovule containing an embryonic sporophyte and a nutritive tissue (endosperm or perisperm) with stored food that sustains the initial growth of the embryo upon germination, except when such food reserve is stored instead in the cotyledon(s) of the embryo itself, these enclosed by one or two integuments (the testa), the whole serving as a propagule. A fertile seed (one containing a viable embryo) normally results from sexual fertilization of an egg by a sperm; however, fertile seeds are sometimes produced asexually by apomictic processes (e.g., parthenogenesis). |
ovuliferous scale |
< cone scale, macrosporophyll (not recommended), megasporophyll |
STRUCTURE |
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A fertile scale in a female cone (megastrobilus), bearing one or two naked ovules, and subsequently seed(s), subtended by and borne closely upon a sterile, fleshy or woody scale sometimes termed a bract scale; in Pinophyta. |