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Actinomorphic flower
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A flower, capable of being divided, by more than one line passing through the middle of the flower, into two equal parts that are mirror images of one another; e.g., in Gustavia (Lecythidaceae), species of Myrtaceae, and species of Rubiaceae. Same as polysymmetric, radially symmetrical, and regular flowers and opposite of zygomorphic, monosymmetric, bilateral, and irregular flowers. This term can refer to other plant parts as well. |
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Aestivation
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The arrangement of the parts of the perianth in the floral bud. |
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Amphitropous
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Referring to an ovule with a curved embryo sac in which the stalk (funicle) is curved such that the tip of the ovule and the base of the stalk are near one another. Compare with anatropous. |
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Androecial hood
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In the Lecythidaceae, the distal part of the ligule that has become modified either structurally by coiling inward or by the production of staminodes, vestigial stamens, or nectar-producing vestigial stamens. Androecial hoods are usuallly separated from the staminal ring by an appendage-free part of the ligule (the only known exception is Couroupita nicaraguarensis and perhaps a species of the Lecythis sec. Pisonis group not yet identified. Androecial hoods of Lecythidaceae vary according to their degree of structural complexity and the type of androecial appendages they possess. |
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Androecium (plural = androecia)
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The collective term for the staminate structures (i.e., the stamens and staminodes) of a flower; the stamens as a unit. |
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Androgynophore
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A stalk that is elevated above the point of perianth attachment and supports the androecium and gynoecium; e.g., species of Passifloraceae. |
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Androphore
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A stalk elevated above the point of perianth attachment and supporting the stamens; e.g., the united filaments of species of Menispermaceae and Myristicaceae. |
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Andropodium
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In the Podostemaceae, a stalk formed as the result of fusion of the filaments. |
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Antepetalous
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Referring to structures, usually stamens, inserted opposite or facing the petals. |
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Antesepalous
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Referring to structures, usually stamens, inserted opposite or facing the sepals. |
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Anther
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The pollen-bearing part of the stamen. |
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Anther dehiscence lateral
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Referring to the anthers of many flowering plants that open along the side. |
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Anther sac
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See theca. |
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Anther versatile
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A stamen in which the filament is attached to the anther above the base of the anther. |
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Antheriferous
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Bearing anthers. |
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Antherode
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The anther of a staminode; an anther that bears pollen that does not germinate; in the Lecythidaceae, antherodes are found in the androecial hood and in the innermost row of anthers on the ligular side of the staminal ring of some species, in the Lecythidaceae antherodes are often different in color, usually yellow, than the anthers of the stamens which are usually white. |
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Anthers basifixed
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Referring to an anther attached to the filament at its base. |
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Anthesis
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The expanding and opening of a flower. |
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Antipodals
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Three cells located at the end of the matural megagametophyte opposite the micropyle. These cell apparently have no function and desintegrate after fertilization. |
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Apetalous flower
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Without petals. |
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Apical placentation
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A type of placentation in which the ovules are attached at the apex of the locule. See placentation. |
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Apotropous
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Referring to an ovule with a ventral raphe. |
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Ascending-cochleate
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Referring to a type of corolla aestivation in the Acanthaceae in which one petal, being larger than the others covers the other petals in bud. |
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Asymmetric flower
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Same as zygomorphic flower. |
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Aureole
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See eyespot. |
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