Panicum L. sect. Rudgeana (Hitchc.) Zuloaga, P. sect. Urvilleana (Hitchc. & Chase) Pilger, and unplaced species of P. subg. Panicum (Poaceae: Panicoideae: Paniceae) in Brazil

Abstract

Panicum L. subg. Panicum includes around 100 predominantly tropical species. Of these species, approximately 50 are American, which occur from Canada to Argentina, Uruguay, and Brazil. In Brazil, this subgenus is represented by 30 species. Three of these species (P. complanatum Guglieri, Longhi-Wagner & Zuloaga, P. mystasipum Zuloaga & Morrone e P. olyroides Kunth)  have not been placed in a defined section and the remaining species are included in sections Dichotomiflora (Hitchc. & Chase) Honda, Panicum, Rudgeana (Hitchc.) Zuloaga, Urvilleana (Hitchc. & Chase) Pilger, and Virgata Hitchc. & Chase ex Pilg. The aim of this paper is to provide means for the identification of the Brazilian species of Panicum sect. Rudgeana, P. sect. Urvilleana, and the unplaced species of P. subg. Panicum, which will contribute to the knowledge of the Brazilian flora and provide data for other areas of research. We performed a literature review, analyzed specimens in national and foreign herbaria, collected and observed plants in the field, as well as studied the surface of the second anthecium using scanning electron microscopy (SEM). Panicum sect. Rudgeana includes five neotropical species, all occuring in Brazil, in cerrado and campo rupestre. Panicum sect. Urvilleana  includes three neotropical species, of which only one occurs in Brazil on coastal dunes. Panicum complanatum and P. mystasipum are restricted to  the midwestern and southeastern regions of Brazil, respectively, while P. olyroides spreads to “campo” regions of  southern Brazil. Keys to the species of both sections are given, as well as morphological descriptions, illustrations, and scanning electron images of the upper anthecium surface.