Abstract

Chascolytrum serranum, a new species of C. sect. Hildaea restricted to Serra Geral National Park and surroundings, in Cambará do Sul, Rio Grande do Sul, Brazil, is described and illustrated. The new species is morphologically similar to C. ambiguum and C. juergensii var. angustilemma, but is distinguished from them mainly by having paleas more than 2/3 the length of the lemmas (up to 2/3 the length of the lemmas in C. ambiguum and C. juergensii var. angustilemma), glabrous and smooth lemmas (strigose in C. juergensii var. angustilemma), and puberulous paleas (glabrous in C. ambiguum). The species can be recognized in the field by the purplish and shiny spikelets. It inhabits river banks and, less frequently, swamps.