Reinterpretation of the nomenclatural type of Pseudobombax heteromorphum (Malvaceae, Bombacoideae) reveals an overlooked new species from Bolivia

Abstract

In the course of a taxonomic revision of Pseudobombax Dugand, one of us (JGCS) frequently has observed herbarium specimens of Bombacoideae that comprise a mixture of different Angiosperm families. In particular, Pseudobombax heteromorphum (Kuntze) A. Robyns, a frequent name in checklists of the Bolivian flora, is based on type material of Bombax heteromorphum Kuntze that is clearly a mixture of Pseudobombax flowers and Tabebuia Gomes ex DC. (Bignoniaceae) leaves. We herein designate as the lectotype of Bombax heteromorphum the flowers of an herbarium sheet deposited in NY and as epitype a complete specimen (leaves, flowers, and fruit) in HUEFS. We consider Bombax heteromorphum to be a synonym of Pseudobombax longiflorum (Mart.) A. Robyns, a species widespread in Neotropical seasonally dry forest of Bolivia, Brazil, Paraguay, and Peru. Furthermore, we describe a new species, Pseudobombax pulchellum Carv.-Sobr., apparently endemic to seasonally dry tropical forest (SDTF) in Bolivia (Chiquitano dry forest), based on specimens commonly but incorrectly identified as Pseudobombax heteromorphum.We also comment on the morphology, distribution, and conservation status of this new species.