A New Species of Cissus (Vitaceae) for Central and South America

Abstract

Cissus pseudosicyoides is described as new. The species ranges from Costa Rica to Colombia. Though it has been confused in the herbarium with C. sicyoides L., it is probably more closely related to C. biformifolia Standley with which it shares dimorphic leaves and appressed T-shaped trichomes. It is most easily distinguished from C. sicyoides by having minute puberulence on most parts with occasional T-shaped trichomes and by having pubescent pedicels. It is distinguished from C. biformifolia by being densely puberulent and by having smaller greenish flower buds and smaller fruits. Two unifoliate species of Cissus, C. sicyoides L. and C. biformifolia Standley, were reported in the Flora of Panama (Elias, 1968). In the course of my work on the Barro Colorado Island (Panama) flora, another species has been discovered. Cissus pseudosicyoides, sp. nov. Herba scandens cirrhosa; rami parvi et nervi foliorum trichomatibus brevibus inconspicuis, approximatisque necnon trichomatibus T-formibus, sparsis, adpressisque. Folia alterna, sicco nigrescentes; limbo foliorum majorum ovato-cordato, 9-15 cm longo, 9-12 cm lato, nervis lateralibus utroque latere 3-6; petiolis foliorum majorum 7-11 cm longis; limbo foliorum parviorum anguste ovatis, basi truncato aut obtuso aut acutato, 3-10 cm longo, 2-8 cm lato. Inflorescentia 1-4 cm longa; pedunculo florenti 2-10 mm longo, trichomatibus T-formibus densis adpressis; calyx expansus, + crateriformis, 4-lobatus remote, alabastro latiorus; alabastrum ovoideum, 1.5-2 cm longum; petalum album aut cremeum (ruber aliquando). Fructus + globosus, ad 6 mm diametro, viridis. Flores per initium tempus sicci. Tendrilled herbaceous vine, probably ultimately arising from a woody stem; at least smaller stems, petioles, and veins of leaf blades (especially below) closely and inconspicuously puberulent; the same parts but also the axes of the inflorescence, pedicels, and leaf surfaces often sparsely pubescent with flattened, + appressed T-shaped trichomes; stems of juvenile parts often white-speckled; leaves alternate, thin, usually drying dark, the larger ones borne below the inflorescence, ovate-cordate, as broad or nearly as broad as long, 9-15 cm long and 9-12 cm wide, with 3-6 pairs of lateral veins above sinus, with a single strong trunk vein extending into each basal lobe, the veins extending into apiculate teeth along the margin of the blade, the sinus about as deep as broad; petioles mostly 7-11 cm long; leaves higher on the stem and opposite the inflorescences usually narrowly ovate, smaller and with the base truncate to obtuse or acute at base (rarely cordate at base), mostly 3-10 cm long and 2-8 cm wide with petioles mostly 2-8 cm long, otherwise as the larger leaves. Inflorescences terminal or opposite upper leaves, small, congested, branched, umbelliform cymes 1-4 cm long, about as broad as long; peduncles mostly 2-10 mm long at anthesis (somewhat longer in fruit), densely appressed-pubescent with T-shaped trichomes, densely bracteate at apex, the bracts minute with margins glabrous or very in' Curator of Phanerogams, Missouri Botanical Garden, 2315 Tower Grove Avenue, St. Louis, Missouri 63110. ANN. MISSOURI BOT. GARD. 60: 564-567. This content downloaded from 157.55.39.243 on Thu, 06 Oct 2016 04:54:34 UTC All use subject to http://about.jstor.org/terms 1973] CROAT-A NEW CISSUS 565 conspicuously ciliate; pedicels terete, 1.5-3.5 mm long, sparsely pubescent, the trichomes as on peduncles but usually smaller; calyx spreading, + bowl-shaped, inconspicuously 4-lobed, narrower than the buds, nearly glabrous; buds ovoid, 1.5-2 mm long, drying with ridges along the margins of the petals; corolla of 4 free, broadly oblong petals, these obtuse and cucullate at apex inside, usually white or cream (rarely red); stamens opposite petals; filaments to ca. 1 mm long, equalling or longer than anthers; anthers nearly as broad as long, dehiscing laterally; stigma simple, to ca. 1.5 mm long. Fruits ? globose, to 6 mm in diameter, apparently green at maturity; pericarp and mesocarp thin; seed 1, round, only slightly smaller than the dimensions of the fruit. HOLOTYPE: Panama. Canal Zone: Barro Colorado Island, Clearing at laboratory; vine; fruits green; flowers greenish. 9 January 1969. Croat 7017 (MO). Flowers at the beginning of the dry season in December and January on Barro Colorado Island (rarely elsewhere as late as March) or in the rainy season (late July-October). Individual plants may flower for one month or more. The fruits develop promptly, usually are present with flowers, and are usually gone by March. They are probably dispersed by smallto mid-sized birds. It is not known whether the fruits become brightly colored or not. Observations on Barro Colorado Island indicate that the fruits are probably removed before turning color. Cissus pseudosicyoides ranges from Guanacaste Province of Costa Rica to northern Colombia. It is widespread in lowland areas of Panama, principally from the Pacific slope in drier areas of tropical moist forest but is also known from premontane wet forest at Chiman and premontane dry forest at Juan Diaz