Revision of the Neotropical genus Pseudoxandra (Annonaceae)

A taxonomic revision is made of the Neotropical genus Pseudoxandra. This genus forms part of the Cremastosperma alliance which consists of Bocageopsis, Cremastosperma, Ephedranthus, Klarobelia, Malmea, Mosannona, Onychopetalum, Oxandra, Pseudephedranthus, Pseudomalmea, Pseudoxandra, Ruizodendron, and Unonopsis, all from the Neotropics. Within Pseudoxandra 22 species are recognized, four of which were described quite recently by the first author (Maas et al., 1986). Fourteen species are described here as new. Two dichotomous keys are provided, one for the genera of the Cremastosperma alliance, and the other for the species of Pseudoxandra. The species treatments include descriptions, geographical and ecological notes, distribution maps, synonymy, taxonomic notes, and vernacular names. A complete index of exsiccatae is included. Parallel to the taxonomic revision, a leaf anatomical survey was made by E.-J. van Marle. One of the intriguing features in Pseudoxandra is the frequent presence of minuscule warts on the leaves in dried specimens, while fresh material does not show any such warts. Osteosclereids found in the mesophyll of most species are probably responsible for this feature. This revision is meant as a precursor for a future Flora Neotropica treatment of the integral Cremastosperma alliance. Revisions of Klarobelia, Malmea s.s., Mosannona and Pseudomalmea, once constituting the genus Malmea s.l., were published earlier by Chatrou (1998). Treatments of other genera are under way, or planned for the near future.