Pereskia quisqueyana Alain
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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
Species Description - Shrub 2-4(-5) m tall, main shoots to ca. 10 cm thick; trunk to 25 cm in diam. at base, bark of main shoots smooth, brown; branches with pale brown to greenish-gray, smooth bark; twigs 2-3(-4) mm thick, olive-green to brown, drying pale brown. Roots with fusiform thickenings 20-30 cm long and 5-10 cm thick, fleshy. Areoles rounded, 1-3 mm diam. on twigs, to 15 mm diam. on trunk, with white to light gray or pale brown tomentum of trichomes ca. 1 mm long, producing spines only. Leaves elliptic to obovate-lanceolate, petiolate; base attenuate; apex acuminate or acute-acuminate, variable in size, those of the distal twigs elliptic-obovate, (2-)3-5(-7) x (1.4-)2.5-3.0 cm; petiole ca. 1-5 mm long; blade 0.8 mm thick; midrib prominent below, lateral veins ca. 2-3, inconspicuous; leaves of strong shoots 5-12 x 1.5-2.5 cm; petiole 5-15 mm long, midrib prominent below, lateral veins 3-5(-6), rather inconspicuous. Spines 0-4 on twigs, often lacking on flowering twigs, 10-15 mm long and 0.2-0.4 mm thick, spreading, stiff, pungent, straw-colored to brown with light tip, base not or slightly thickened, increasing in number on branches, to 120 per areole on trunk, 2-6 cm long and 0.5-0.8 mm thick, spreading, pungent. Staminate flowers terminal and on short spur shoots, (4-)5-7 cm in diam.; pistillate flowers not seen; flower buds with subspherical-ovoid corolla; pedicels (0-)2-3 mm long; receptacle 7-8 mm in diam., turbinate-poculiform, green; areoles 3-5, inconspicuous, almost naked or with sparse white wool of trichomes 1 mm long, the lower ones rarely with 1-2 weak spines up to 5 mm long; lower bracts 0-3, leaf-like at the base of the pedicel and receptacle; upper bracts on the rim of the receptacle 0-3, obovate-lanceolate, to 14 mm long and 6 mm broad, thick, green, with midrib prominent below; sepaloids three, obovate, 15-17 mm long and 7-9 mm broad, apex rounded, blade greenish-pink; petaloids ca. 8-9, spreading, obovate-spathulate, (25-)30-35 mm long and 1822 mm broad, pink; base narrow cuneate; apex emarginate; stamens ca. 150, longer than the style, filaments 7-11 mm long, the outer ones longer than the inner ones, pink; anthers 1.6-2.5 mm long and 0.5-0.9 mm broad, dull pink; pollen 12-colpate, medium-sized, tectum perforate and with large spinules; ovary of staminate flowers deeply sunk in the turbinate receptacle, locule ca. 1 mm in diam., placentae in the upper part of the locule, parietal; ovules aberrant; style 4 mm long, 0.5 mm thick, narrower towards the stigma, stigma lobes ca. five, 0.51 mm long, erect, concealed by the stamens, without stigmatic papillae. Fruits unknown.
Distribution and Ecology - Distribution (Fig. 36) and phenology. Endemic to the southeastern part of the Dominican Republic, at sea level in coastal thickets on coral limestone and sand, flowering observed in March and July; only known from the type locality.
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Discussion
Type. Dominican Republic. La Altagracia (“La Romana”): Bayahibe, 9 Jul 1977 (fl), Alain H. Liogier 27032 (holotype, UPR; isotypes, NY, US). The diagnostic characters mentioned in the original description of this species, namely flower and leaf size, hardly seemed to justify specific status as distinct from P. zinniiflora, but examination of the type specimen and further material as well as my own observations at the type locality revealed that the taxon is well delimited by leaf shape, spine color and dimensions, tomentum of the areoles, and size of the anthers. The fusiform thickenings of the roots hitherto only known in Andean species were observed during the same visit at the type locality and in cultivated specimens in the collection of Padre Cicero at San Cristóbal, Dominican Republic. Unless it is found at other localities this plant could become highly endangered due to its extremely small and exposed habitat on the peninsular shoreline near a village with sand beaches. Further observations on the reproductive biology are necessary, because normal ovules and fruit have not been reported yet.