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Flora of North America Glossary

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Term Synonyms Category Limitation Definition
antrorse orientation Directed forward or upward, toward the distal end of the context of reference, parallel or at an acute angle to the bearing structure.
apetalous architecture flower, perianth Lacking petals.
apex pl. apices CHARACTER Configuration of the uppermost, distal, or terminal portion of a structure, its extent determined somewhat subjectively in relation to the shape of the structure as a whole. The concept of apex varies from one descriptive context to another, since the apex is not a clearly delimited, morphologically distinct entity. The terms for describing apical condition are not strictly coordinate logically — some are more inclusive than others, some describe conditions involving what can be regarded as appendages, and some refer to the apex in a developmental as well as a strictly topological sense — and precise characterization may require using more than one descriptor. The semantic antecedent of some descriptors is "apex," whereas the antecedent of others is the structure as a whole (e.g., leaf ).
aphyllous = leafless architecture plant, axis Not bearing leaves.
apical < distal insertion At or very near the developmental end or tip (apex) of a structure.
apical < distal position At or very near the developmental end or tip (apex) of a structure.
apiculate apex Terminating abruptly in a short, slender, angular tip that is not notably harder or stiffer than the main body of the structure. See also mucronate, mucronulate.
apiculum 1 pl. apicula STRUCTURE A short, slender, angular tip that is not notably harder or stiffer than the main body of the bearing structure. See also mucro.
apiculum 2 pl. apicula STRUCTURE The apex of a connective, when prolonged above the union of the anthers.
apocarpous architecture flower, gynoecium Having two or more simple pistils (carpels).
apogamous < apomictic, asexual reproduction taxon, plant Producing new sporophytes from the gametophytes asexually, without intervening fertilization (or gametes).
apolar architecture pollen grain, spore Lacking morphologically evident polarity.
apomictic = asexual; > agamospermous, apogamous, aposporous, vegetative reproduction taxon, plant Producing new plants by means not involving meiosis or fertilization.
apopetalous = choripetalous, dialypetalous, polypetalous architecture flower, perianth, corolla Having two or more distinct petals; having the petals unfused.
aposepalous = chorisepalous, dialysepalous, polysepalous architecture flower, perianth, calyx Having two or more distinct sepals; having the sepals unfused.
aposporous < apomictic, asexual reproduction taxon, plant Producing new gametophytes from the sporophytes asexually, without intervening meiosis (or spores).
apostemonous architecture flower, androecium Having two or more distinct stamens; having the stamens unfused.
apotropous orientation ovule Anatropous but the whole recurved such that the raphe (adnate portion of the funiculus) faces the ovary wall (placenta) and the ovule is parallel to it, the micropyle facing the free basal portion of the funiculus.
appendage STRUCTURE Any subordinate structure ontogenetically derived from and associated with a given organ or part.
appressed orientation lateral structure Angled at or near the base and closely flattened against the surface of the bearing structure, thus more or less parallel to it.
approximate = close arrangement Disposed relatively near to one another.
aquatic habit plant Growing in water.
arachnoid = cobwebby pubescence Of fairly sparse, fine, white, loosely tangled, capillate trichomes.
arboreous < tree-form habit plant Having the character of a tree. See also arborescent, bushy, frutescent, fruticose, subshrubby, suffrutescent, suffruticose, woody-clumping.
arborescent < tree-form habit plant Developing the character of a tree. See also arboreous, bushy, frutescent, fruticose, subshrubby, suffrutescent, suffruticose, woody-clumping.
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