Actinocephalus pachyphyllus: re-establishment, redefinition, and a new combination in Eriocaulaceae from Brazil

Abstract

We report the rediscovery of Paepalanthus macrocephalus var. pachyphyllus, an obscure taxon known exclusively from the type specimen. We formally re-establish the species Paepalanthus pachyphyllus and propose its combination within Actinocephalus. The species is redefined and illustrated. Actinocephalus pachyphyllus F. N. Costa, Trovo & Echtern. (Eriocaulaceae, Paepalanthoideae) is distinguished from closely related species by possessing cylindrical to canaliculate linear leaves, covered by long trichomes at the base, with a round to obtuse apex, and short paraclades bearing a single scape. The species is endemic to the Espinhaco Range in Minas Gerais. We compare it with Paepalanthus glareosus (Bong.) Korn. and P. trichopeplus Silveira, the most morphologically similar species. Comments on morphological variation, habitat, geographic distribution, conservation status as well as line drawings, photos, and a distribution map are provided.