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Perigynous ovary
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Referring to a flower in which the sepals, petals, and stamens arise from the rim of a cuplike hypanthium surrounding the ovary. |
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Peripheral filaments
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Protein filaments associated with sieve-element plastids. |
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Personate
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Referring to a bilabiate corolla with an expansion on the lower lip that blocks entry into the tube; e.g., in some species of Acanthaceae. |
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Petal
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An outermost segment of the corolla. |
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Petal lobe
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A lobe of the corolla that arises from the corolla tube. |
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Pistil
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The female part of the flower composed of the ovary, style, and stigma. |
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Pistillate flower
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Referring to unisexual flowers with functional gynoecia but without functional stamens (staminodes may be present). Same as female flower. |
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Pistillode
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A rudimentary, sterile gynoecia. |
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Placenta (plural = placentae)
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The structure in the ovary to which the ovules are attached. |
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Placental obturator
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A massive outgrowth of the placenta. In the Styracaceae, the micropyle of each ovule opens upon an obturator; the obturators may or may not be connate. |
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Placentation
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In broadest terms, the arrangement of ovules within the ovary. See axile, basal, free-central, and parietal placentation. |
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Placentation basal
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A type of placentation in which the ovule is attached to the floor of the locule. |
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Placentation free-central
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A type of placentation in which the ovules are borne on a central column arising from the base of a unilocular ovary. |
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Polar nuclei
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Two nuclei that migrate to the center of the embryo sac and fuse with a male nucleus (sperm) to form the primary endosperm nucleus which divides and sometimes forms the endosperm. |
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Pollen
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Male reproductive structures contained within the anther of the stamen and usually released at anthesis. Same as microgametophytes. |
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Pollinarium (plural = pollinaria)
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The pollen-bearing structure of Orchidaceae composed of a viscidium, a stipe, and pollinia. |
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Pollinium (plural = pollinia)
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An aggregate pollen mass characteristic of Orchidaceae and those of Apocynaceae subfamily Asclepiadoideae. |
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Polyandrous
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Referring to an androecium with numerous stamens. Same as polystemonous. |
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Polypetalous corolla
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Having petals free from one another. Same as choripetalous; opposite of sympetalous. |
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Polystemonous
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Having many stamens. Same as polyandrous. |
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Polysymmetric 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 acinomorphic, 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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Poricidal anther dehiscence
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Referring to anthers that shed their pollen via terminal apertures; e.g., Gustavia spp. (Lecythidaceae) and Solanum spp. (Solanaceae). |
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Pseudanthium (plural = pseudanthia)
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A false flower; e.g., the inflorescence of species of Asteraceae and Dalechampia (Euphorbiaceae). |
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Pseudodisc
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In some Menispermaceae, the button-shaped fleshy whorl of petals. |
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Pseudostaminodia (singular = pseudostaminodium)
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In the Amaranthaceae, referring to sterile, filamentous, entire to fimbriate processes as long as or longer than the stamens and alternating with them. |
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Pterophyll
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Expanded sepal (usually white or green) of some Rubiaceae that usually are expanded fully after anthesis and aid in wind dispersal. |
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Rachilla
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The axis of a spikelet of a Cyperaceae or a Poaceae along which are placed the florets. |
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Radially symmetrical 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 actinomorphic, polysymmetric, 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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Radially symmetrical pollen
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In the Malpighiaceae, referring to pollen with pores on the equator and colpi, if present, oriented at right angles to the equator. |
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Ray flower
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A zygomorphic flower with a straplike corolla found in Asteraceae. Compare with disk flower. |
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Receptacle
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The more or less expanded apex of the axis beyond the pedicel upon which the floral parts are borne. |
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Receptacular throat
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In the Cactaceae, the part of the receptacle above the receptacular tube. |
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Receptacular tube
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In the Cactaceae, the broadened part of the receptacle between the summit of the ovary and the point at which the receptacle begins to broaden. Same as epigynous hypanthium. |
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Recepticle
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The thickened part of the pedicel from which the flower organs or the fruits arise. In some accessory fruits, for example the pome and strawberry, the receptacle gives rise to the edible part of the fruit. |
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Regular 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 actinomorphic, polysymmetric, and radially symmetrical flowers and opposite of zygomorphic, monosymmetric, bilateral, and irregular flowers. This term can refer to other plant parts as well. |
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Resupinate
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Turned 180° in development; e.g., flowers of the Orchidaceae in which the lip originates in the uppermost position but twists 180° so it facing downward at anthesis. Most orchids have resupinate flowers. |
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Rostellum (plural = rostella)
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The portion of the stigma of some Orchidaceae that separates the anther from the fertile part of the stigma and aids in gluing the pollinia to the pollinators; a small beak. |
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Rotate
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Disk-shaped or flat and circular, usually referring to a sympetalous corolla with a short tube and very widely spreading lobes. |
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Salverform
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Referring to the shape of a sympetalous corolla in which the tube is slender and the lobes are abruptly spreading and flat. Same as hypocrateriform and more frequenly used by authors than that term. |
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Sectile
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Referring to the aggregate clumps of soft, granular pollen which distinguishes some species of Orchidaceae. In these species the pollen is easily separated and not aggregated in distinct pollinia. |
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Sectile pollen
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Referring to the aggregate clumps of soft, granular pollen which distinguishes some species of Orchidaceae. In these species the pollen is easily separated and not aggregated in distinct pollinia. |
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Sepal (sepals)
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A segment of the calyx. |
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Septal nectary
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A nectary developing in the septal regions of the ovary. |
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Septal region
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The part or parts of the ovary associated with the septa. |
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Simple pistil
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A gynoecium composed of a single carpel. |
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Simple style
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Referring to a style that is not divided at the apex. |
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Spathella
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Saclike covering of the young flowers of Podostemaceae. |
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Spur
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A tubular, usually nectar-producing outgrowth of a part of a flower; e.g., part of the sepal in some Vochysiaceae. |
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Stamen
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The male part of the flower comprised of the filament and the anther; in the Lecythidaceae stamens are found attached to the staminal tube in those genera that have one (Allantoma, Cariniana, Grias, and Gustavia) and, as far is known, to the staminal ring of species with zygomorphic flowers. Stamens associated with the ligule are hypothesized to be staminodes bearing antherodes and not anthers. |
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Stamens
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The male part of the flower comprised of the filament and the anther. |
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