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RANUNCULACEAE
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RANUNCULACEAE , in See also:botany, a natural See also:order of See also:Dicotyledons belonging to the subclass Polypetalae, and containing 27 genera with about Soo See also:species, which are distributed through temperate and See also:cold regions but occur more especially beyond the tropics in the See also:northern hemisphere. It is well represented in See also:Britain, where 11 genera are native. The See also:plants are mostly herbs, rarely shrubby, as in See also:Clematis, which climbs by means of the See also:leaf-stalks, with alternate leaves, opposite in Clematis, generally without stipules, and See also:flowers which show considerable variation in the number and development of parts but are characterized by See also:free hypogynous sepals and petals, numerous free stamens, usually many free one-celled carpels (fig. 2) and small seeds containing a See also:minute straight embryo embedded in a copious endorsperm. The parts of the See also:flower are generally arranged spirally on a See also:convex receptacle. The See also:fruit is one-seeded, an achene (fig. 3), or a many-seeded follicle (fig. 4), rarely, as in Actaea, a See also:berry. From Vines's Students' See also:Text See also:Book of Botany, by permission of See also:Swan, Sonnenschein & Co.. From Strasburger's Lehr-Mich der Botanik, by per-See also:mission of Gustav See also:Fischer. represented among See also:British native or commonly grown See also:garden plants. Tribe I. Paeonieae, peony See also:group, are mostly herbs with deeply cut leaves and large solitary showy flowers in which the parts are spirally arranged, the sepals, generally five in number, passing gradually into the large coloured petals. The indefinite stamens are succeeded by 2–5 free carpels which See also:bear a See also:double See also:row of ovules along the ventral suture. See also:Honey is secreted by a See also:ring-like swelling See also:round the See also:base of the carpels, which become fleshy or leathery in the fruit and dehisce along the ventral suture. There are only three genera, the largest of which, See also:Paeonia, occurs in See also:Europe, temperate See also:Asia and western See also:North See also:America. P. officinalis is the See also:common peony. Tribe II. Helleboreae are almost exclusively north temperate or subarctic; there are 15 genera, several of which are represented in the British See also:flora. The plants are herbs, either See also:annual, e.g. Nigella (love-in-a-mist), or perennial by means of a rhizome, as in Aconitum or Eranthis (See also:winter See also:aconite). They leaves are See also:simple, as in Caltha, but 'more often palmately divided as in See also:hellebore (fig. 6), aconite (fig. 5) and See also:larkspur. The flowers are solitary (Eranthis) or in
cymes or racemes, and are generally See also:regular as in Caltha (See also: 8). The parts of the flower are gene- rally arranged in a See also:spiral (acyclic), but are sometimes hemicyclic, the perianth forming a whorl as in winter aconite; rarely is the flower cyclic, as in Aquilegia (fig. 9) where the parts throughout are arranged in alternating whorls. In Caltha, where there are no petals, honey is secreted by two shallow depressions on the side of each carpel. Tribe III. Anemoneae, with 8 genera, are chiefly north temperate, See also:arctic and alpine plants, but also pass beyond the tropics to the See also:southern hemisphere. They differ from the two preceding tribes in the numerous carpels, each with only one ovule, forming a fruit of numerous achenes. They are annual or perennial herbs, erect as in See also:Anemone, Thalictrum (meadow-See also:rue) and many buttercups, orcreeping as in See also:Ranunculus repens; the See also:section Batrachium of the genus Ranunculus (q.v.) contains aquatic plants with submerged or floating stems and leaves. The flowers are solitary, as in Anemone Pulsatilla (Pasque flower) and the See also:wood anemone, or cymose as in species of Ranunculus, or in racemes or panicles as in Thalictrum. The parts are spirally arranged throughout as in Myosurus (See also:mouse-tail), where the very numerous carpels are See also:borne on a much elongated receptacle, or See also:Adonis (See also:pheasant's See also:eye), or the perianth is whorled as in Anemone and Ranunculus. In Anemone there is a whorl of foliage leaves below the flower, as in Eranthis. In Anemone and Thalictrum there is only one series of perianth leaves, which are petaloid and attractive in Anemone where honey is secreted by modified stamens, as in A. Pulsatilla, or, as in A. nemorosa (wood anemone), there is no honey and the flower is visited by insects for the See also:sake of the See also:pollen; in Thalictrum the perianth is greenish or The order falls into several distinguished by characters of well-defined tribes which are the flower and fruit; all are c9s''- -See also:ski slightly coloured and the flower is See also:wind-pollinated (T. minus) or visited for its pollen. In Ranunculus and Adonis a calyx of green protective sepals is succeeded by a corolla of showy petals; in Ranunculus (fig. so) there is a basal honey-secreting gland which is absent in Adonis. In Anemone the achenes bear the persistent naked or bearded See also:style which See also:aids in dissemination; the same purpose is served by the prickles on the achenes of Ranunculus arvensis. Tribe IV. Clematideae comprise the genus Clematis (q.v.), characterized by its shrubby, often climbing See also:habit, opposite leaves and the valvate, not imbricate as in the other tribes, See also:aestivation of the sepals. The usually four sepals are whorled and petaloid, the numerous stamens and carpels are spirally arranged; the flowers are visited by insects for the sake of the abundant pollen. The fruit consists of numer- ous achenes which are generally prolonged into the long feathery style, whence the popular name of the British species, old See also:man's See also:beard (Clematis vita/ha). The genus, which contains about 170 species, has a wide See also:distribution, but is rarer in the tropics than in temperate regions. See also:Special articles will be found on the more important genera of Ranunculaceae, e.g. Aconitum, Adonis, Anemone, Baneberry (Actaea), Clematis, Columbine, Hellebore, Ranunculus. Additional information and CommentsThere are no comments yet for this article.
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