The Mexican and Central American Species of Adelobotrys (Melastomataceae)

Abstract

Adelobotrys, a neotropical genus comprising ca. 25 described species, is largely restricted to the Amazon basin and adjacent regions of South America. The Mexican and Central American species represent geographical fringe elements of the genus and show no close similarities to one another. Adelobotrys panamensis and A. jefensis are described as new and presented in the context of a regional revision with a key, descriptions, brief discussions, illustrations and citation of representative specimens. Adelobotrys, comprising some 25 described species is one of five merianioid genera currently recorded from tropical regions north of the South American continent. Although centered in the Amazon basin, Adelobotrys ranges south to Bolivia, east to Surinam and north through Central America to southern Mexico and Jamaica. The genus has never been the subject of a comprehensive revision but information gleaned from descriptions of new species and regional floristic accounts indicates that Adelobotrys is typically a genus of lowland rainforest habitats. Some species grow at elevations as high as 1,000 meters and a few are apparently restricted to the lower elevation montane slopes which are frequently shrouded in mist because of their geographic position and exposure. In this paper I describe two new Panamanian species of local distribution which fall into the latter category. These novelties are described in the context of a regional treatment with a key and descriptions that will readily facilitate identification and comparison of the Mexican and Central American species. The species considered here represent geographical fringe elements of the genus and for this reason it is not surprising that they show no close similarities to one another. Each appears to have closest affinities with a different group of South American species but a confident assessment of relationships must await critical 'study of the entire genus. ADELOBOTRYS DC., Prodr. 3: 127. 1828 Erect shrubs, small trees to 3.5 m, scandent woody vines or hemiepiphytes adhering to tree trunks by adventitious roots. Internodes glabrous to variously pubescent, terete or ? compressed and 2-edged. Leaves opposite, decussate or distichous, those of a pair equal to slightly unequal, petiolate or subsessile, glabrous or variously beset with malpighiaceous trichomes. Inflorescence terminal