A Synopsis of the Genus Blakea (Melastomataceae) in Mexico and Central America

Abstract

A regional synopsis of the genus Blakea is presented that recognizes 33 species in Mexico and Central America. This summary includes a key, distributional and phenological information, notes on morphological variation, and discussions that provide rationale for relegating six binomials to synonymy. Descriptions and diagnoses are presented for four new species of Blakea (B. coloradensis, B. darcyana, and B. perforata from Panama; and B. wilsoniorum from southern Costa Rica and Panama). Analysis of the type specimens and recently collected flowering material of Topobea storkii necessitates its transfer to Blakea. Three other species (B. cuatrecasii, B. repens, and B. subconnata var. obtusa), all of which were previously known from Andean South America, are reported from Panama for the first time. Blakea, with approximately 100 species, is one of two berry-fruited genera comprising the natural neotropical tribe Blakeeae (Almeda, 1990). It is best represented in wet montane regions from southern Mexico and the West Indies to Bolivia and Brazil. Although northwestern South America is undoubtedly the center of species richness for Blakea (Wurdack, 1973), southern Central America is clearly the area of focal importance for unusual diversity in floral morphology. This floral diversity reflects adaptations to a broad array of important pollinators in the region, including rodents, buzzing bees, and hummingbirds (Almeda, 1990; Lumer, 1981; Lumer & Schoer, 1986). For a woody genus with showy, often spectacular, flowers, it is surprising that Blakea has escaped the attention of serious students until recently. The genus has not been treated in its entirety since Cogniaux's (1891) familial monograph. Even the most recent floristic treatments of the family Melastomataceae for the Mesoamerican region appeared over 30 years ago (Gleason, 1958; Standley, 1924, 1938; Standley & Williams, 1963; Winkler, 1965) when many areas were still little-explored and poorly known botanically. The account presented here is a precursor to the treatment that will appear in Flora Mesoamericana. Four new species and one new generic transfer are proposed in the context of a regional synopsis. This summary also includes a key to the 33 recognized species, distributional and phenological information, notes on variation, and discussions that provide rationale for relegating previously recognized species to synonymy.