A revision of Pusillanthus Kuijt for Brazil is presented. The recently described monotypic genus occurs in Venezuela, Guyana, and Brazil. In Brazil, it is distributed only within the Caatinga domain, in the states of Alagoas, Bahia and Paraíba. The new combination Pusillanthus pubescens (Rizzini) Caires is proposed and the species Phthirusa caatingae Rizzini, Pusillanthus trichodes (Rizzini) Kuijt, and Struthanthus pubescens var. bahiensis Rizzini are treated as its taxonomic synonyms. An illustrative plate and a distribution map for the genus in Brazil are presented, as well as information about leaf architecture, and stem, leaf, and pollen grain surfaces (based on scanning electron microscopy).
Caatinga; ginomonoecy; leaf architecture; Northeast Brazil; Pusillanthus pubescens
