Pereskia
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Authority
Leuenberger, Beat E. 1986. Pereskia (Cactaceae). Mem. New York Bot. Gard. 41: 1-140.
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Family
Cactaceae
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Scientific Name
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Description
Genus Description - Leafy and spiny trees, shrubs, or scramblers, sometimes with fleshy, tuberous root thickenings; twigs straight or slightly zigzag, with green cortex; epidermis with few to numerous stomata and retarded periderm formation, or stomata lacking, cuticle thin and periderm formation precocious; epidermis glabrous, or rarely with minute papillae; bark smooth or longitudinally fissured. Areoles in the axils of deciduous leaves, sparsely to densely tomentose with uniseriate and sometimes multiseriate trichomes, producing spines and sometimes brachyblast leaves. Leaves alternate, broad, flat, exstipulate, petiolate to subsessile, somewhat fleshy, deciduous; margin entire, sometimes undulate; venation pinnate or pseudopalmate. Spines solitary, paired, or numerous, uniform but unequal in length, rarely dimorphic and then the first spines paired, claw-like and recurved, straight or nearly so, acicular to subulate, sometimes with markedly broadened, conical base, sometimes lacking on flowering twigs but increasing in number on the trunk. Flowers solitary, terminal or axillary, or in a racemose, paniculate or cymose-paniculate inflorescence sometimes by proliferation from the flower receptacle; flowers hypogynous-perigynous to epigynous; receptacle with few to many areoles, smooth or with prominent podaria, rarely naked except for the receptacular rim; receptacular areoles with sparse to dense tomentum, rarely spiny or with coarse longer hairs; receptacular bracts leaf-like to scaly, somewhat fleshy, the lower ones spreading, the upper ones erect and appressed in bud, green or sometimes tinged like the sepaloids; perianth multiseriate, the segments few to numerous, free; sepaloids somewhat intermediate between bracts and petaloids, lacking axillary areoles and partly tinged like the petaloids; petaloids spreading, rotate, rarely erect and forming a campanulate-urceolate corolla; staminodial hairs rarely present between petaloids and stamens; stamens numerous; filaments inserted at the base of the perianth and shorter than it; ovary superior to inferior, unilocular, with septal ridges at the ovary roof only, or rarely septate with pocket-like locules around a central conical columella; placentae "basal-axile," "basal," or parietal; style shorter to longer than the stamens; stigma lobes 3-20, erect to spreading! Fruit solitary, or clustered-proliferous, or in axillary clusters, rarely in a racemose or paniculate infructescence; fruit pear-shaped, turbinate, globular or broadly depressed-obovate, terete or angled, with narrow to broad umbilicus and persistent or deciduous flower remnants and persistent or deciduous leafy or scaly bracts; fruit wall formed mostly by the receptacle, fleshy to juicy, often rich in mucilage, rarely with fusiform sclereids; locule hollow or filled by a pulp formed by the accrescent funicles. Seeds few to numerous, obovate to lenticular reniform, 1.8-7.5 mm long, with black, mostly smooth and glossy testae, the micropylar end rounded to nose-like; hilum flat to prominent, whitish, small but conspicuous. Embryo strongly curved around the starchy perisperm; cotyledons foliaceous, flat or obvolute.
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Discussion
Type species: Pereskia aculeata Miller (=Cactus pereskia Linnaeus, cf. Britton & Rose, 1919). Named as a tribute to the French scholar Nicolas Claude Fabri de Peiresc (1580-1637). Rhodocactus (A. Berger) F. Knuth in Backeberg & Knuth, Kaktus-ABC 48, 96. 1935. Type. Pereskia grandifolia Haworth (cf. Backeberg, 1958, 113). León & Alain, Fl. Cuba 3: 359, 360. 1953; Backeberg, Cactaceae 1: 113-118, figs. 47-53. 1958; Backeberg, Kakteenlexikon, 395-397, figs. 370-372. 1966.
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Distribution
A neotropical genus of 16 species, ranging from southern Mexico and the West Indies to northern Argentina and Uruguay, primarily in the lowlands.