Conceveiba parvifolia (Euphorbiaceae), a New Species from Panama and Colombia

Abstract

Conceveiba parvifolia from Darien, Panama, and Antioquia, Colombia, is described and illustrated. Two wind-thrown trees encountered on the forested slopes above the abandoned Cana gold mine in Dari6n are apparently the first known representatives of the genus Conceveiba Aublet from Panama, although the genus was previously known from both neighboring Costa Rica and Colombia. Specimens from these two trees key readily to the subtribe Conceveibinae of the Alchorneae (Acalyphoideae) in Webster's synopsis (1994). Within that subtribe, however, the Panamanian collections combine characters currently used to distinguish Conceveiba and Gavarretia Baillon, i.e., on the one hand the sepals of the pistillate flower are separate (usually), the style branches blunt, and the anthers muticous (as in Conceveiba), while on the other hand the sepals of the pistillate flower are eglandular, and the ovary is 2-locular (as in Gavarretia, although some species of Conceveiba are similarly eglandular). The generic boundaries were not clear in this subtribe even before this intermediate taxon further blurred them, and I have chosen to name the new species in Conceveiba since I agree with Webster (1994) that Mueller's inclusion (1874) of Gavarretia as a section of Conceveiba may be justified. Conceveiba parvifolia McPherson, sp. nov. TYPE: Panama. Darien: near Cana mine S of El Real (Cerro Pirr6 massif), 7?45'N, 77?40'W, ca. 900 m, 26 Aug. 1987, McPherson 11607 (holotype, PMA; isotypes, BM, COL, CR, DAV, EAP, F, G, GH, HUA, K, MEXU, MICH, MO, NY, P, US). Figure 1. Species foliis minoribus (2.7-16.5 cm X 0.8-5.5 cm), inflorescentiis masculis brevibus (10 cm) fere eglandulatis, floribus masculis non fasciculatis, sepalis floris feminei 4(-5) eglandulatis, ovario biloculari, stylis 2 semiconnatis a congeneribus diversa. Tree (6-)15-20 m; colored exudate absent; youngest branches stellate-puberulent, without lenticels, terete or somewhat ridged, the older ones glabrate and bearing elongated lenticels. Leaf blade (2.7-) 3.5-8.0(-16.5) cm long, (0.8-)1.8-4.0(-5.5) cm wide, elliptical-oblong, obtuse at the base, acuminate at the apex, the margin crenate (sometimes obscurely so) with 5-8 mucronate teeth, the upper surface sparsely stellate-puberulent before maturity, rapidly glabrate, the lower surface densely stellate-puberulent before maturity, eventually glabrate, often with 1-several embedded glands, secondary veins 6-10 on each side of the midrib, the reticulum slightly raised on the upper surface and more strongly raised on the lower; petiole 1.34.0(-4.8) cm long, 0.5-1.0 mm diam., semicircular in cross section, sparsely stellate-puberulent, a distal pulvinus usually discolored and thereby distinguishable, 2-3 mm long, sometimes slightly swollen, a smaller proximal pulvinus often present; stipules subulate, 2-4 mm long, up to 0.5 mm wide, stellate-puberulent, quickly caducous. Plants dioecious; inflorescences terminal or from the axils of the most distal leaves. Staminate inflorescences paniculate or less often racemose, up to 10 cm long, the axes stellate-puberulent, bracts triangular, up to 2 mm long, stellate-puberulent, each bract often accompanied by two smaller bracteoles, both bracts and bracteoles sometimes bearing weakly differentiated glabrous glandular patches; pedicels 1-1.5 mm, not fasciculate, glabrous; buds ca. 2 mm diam., apiculate; sepals valvate, 2 or 3 in number, 2.5-3.5 mm long, up to 3 mm wide, concave, eglandular, green, glabrous without, somewhat granularpuberulent within at base of filaments; petals and disk absent; stamens 35-42, filaments up to 3 mm long, free or the central ones connate basally, glabrous, anthers ca. 0.8 mm long, rounded, somewhat puberulent; pistillode absent. Pistillate inflorescences racemose, up to 5 cm long (occasionally the most proximal flowers subtended by only slightly modified leaves), the axes stellate-puberulent, eglandular; bracts not seen, rapidly caducous; pedicels 4-13(-18) mm long, somewhat inflated distally, stellate-puberulent, usually bearing two bracteoles ca. 2 mm long, these caducous, usually attached near the pedicel base but sometimes attached subapically and then mistakable for sepals; NovoN 5: 287-289. 1995. This content downloaded from 157.55.39.183 on Thu, 26 May 2016 06:05:52 UTC All use subject to http://about.jstor.org/terms