A New Species of Dicranostyles (Convolvulaceae) from Venezuela

Abstract

A new species of Dicranostyles, D. costanensis, is described from the Costal Cordillera and lowland forests of Apure State, Venezuela. The collections of this species extend the known range of the genus northwest of the llanos. At the Instituto Botanico in 1967 we discussed collections of a new species of Dicranostyles from the cloud forests of the Venezuelan Coastal Cordillera. Because the junior author had been studying that genus and the related genera Lysiostyles and Maripa, it was decided that we would publish the new Venezuelan species together. The collections of D. costanensis are the first made from northern and northwestern Venezuela and extend the range of the genus north of the South American llanos. Dicranostyles costanensis Steyermark & Austin, sp. nov. A D. scandenti affinis et cum ea ovario glabro, sed thyrsis longioribus, tomento densiore et magis cinnamomeo vel castaneo, floribus densioribus, foliis basis obtusis vel subrotundatis, corollis et stylis longioribus, et distributis in et circa montibus costanensis Venezuelis differt. Etiam similibus a D. ampla var. ampla, sed ovario pubescenti et regna Amazona habitat distincta est. Lianas; stems gray-red to reddish-brown, smooth, with white lenticels. Leaves with petioles 12-20 mm long; blades oblong, elliptic-oblong to ovate, 4-9 (-12) cm long and 3-5 cm wide, the base subrotund to obtuse, the apex acuminate, thinly coriaceous, the secondaries 8-13 pairs; glabrescent on both sides. Inflorescences axillary, aphyllothyrsiform, 4-18 cm long, densely cinnamon-brown pubescent; bracts 1-2 mm long, oblong, acute, pubescent. Flowers with pedicels ca. 1 mm long; sepals deltoid-suborbiculate, obtuse, 1.5 mm long and 1.9-2 mm wide, pubescent without, glabrous within, margins ciliolate with non-glandular trichomes; corolla subrotate, white, ca. 5 mm long and ca. 5 mm wide, the tube short, ca. 1.2 mm long, ca. 2 mm wide at summit, ca. 1.5 mm wide at base, glabrous without, the lobes elliptic-oblong, thickened and subinflexed at the acute apex, ca. 3.5 mm long and ca. 1.8-1.9 mm wide, pubescent without, glabrous within; stamens excluded, the filaments ca. 3 mm long, inserted ca. 1 mm above corolla base, basally glandular pubescent, the anthers ca. 1 mm long, oblong, basally sagittate; ovary conic-oblong, ca. 1 mm long and ca. 0.5 mm in diameter, glabrous, the styles 2, free for 0.5-1.5 mm, mostly united in basal 0.3-0.7 mm, total length ca. 2 mm, glabrous, the stigmas capitate to ? complanate and irregularly lobed. Fruits ellipsoid, 22-25 mm long and 17-19 mm in diameter, striae 1Instituto Botanico, Ministerio de Agricultura, Caracas, Venezuela. 2Missouri Botanical Garden and Department of Biology, Washington University, St. Louis, 63130. Present address: Department of Biological Sciences, Florida Atlantic University, Boca Raton, Florida 33432. ANN. MISSOURI BOT. GARD. 57: 155-157. 1970. This content downloaded from 207.46.13.71 on Wed, 27 Apr 2016 05:29:46 UTC All use subject to http://about.jstor.org/terms [VOL. 5 7 156 ANNALS OF THE MISSOURI BOTANICAL GARDEN FIGURE 1. Dicranostyles costanensis-A. Habit.-B. Flower.-C. Bud before complete anthesis.-D. Detail of stamens and attachment.-E. Detail of gynoecium.-F. Detail of immature gynoecium dissected from bud. [After Steyermark et al. 100263 (VEN).] This content downloaded from 207.46.13.71 on Wed, 27 Apr 2016 05:29:46 UTC All use subject to http://about.jstor.org/terms