A New Genus of Podostemaceae from Venezuela

The new genus Autana C. T. Philbrick and species A. andersonii C. T. Philbrick are illustrated and described. The new species is documented from four rivers that drain into the Orinoco River, Amazonas, Venezuela. Autana is distinguished by three characters that do not occur in other Neotropical Podostemaceae. The upper surface of the flattened stem has an anastomosing pattern that is derived from a continuation of leaf margins. When the capsule is mature, the pedicel apex (and receptacle) is swollen and hollow. After anthesis, locations where the deciduous stamens attached become darkened and shaped like an inverted teardrop. Phylogenetic analyses indicate A. andersonii is sister to a clade containing species of Castelnavia Tul. & Wedd., Oserya Tul. & Wedd., Noveloa C. T. Philbrick, and Rhyncholacis Tul., as well as upright stemmed species of Apinagia Tul., and Central American and Mexican species of Marathrum Bonpl.