A new species of Rhodospatha (Araceae), with a key to species from the Atlantic Rainforest, Brazil

The subfamily Monsteroideae (Araceae) is principally represented by two genera in the Atlantic Rainforest, Monstera Adans. and Rhodospatha Poepp., which are frequently found in dense ombrophilous, semideciduous seasonal, and deciduous seasonal forests (Coelho et al., 2009). The genus Monstera was revised in the late 1970s (Madison, 1977) and, although new species of Rhodospatha have been described (e.g., Croat, 1999, 2005, Croat, et al., 2005), no review has been presented since the classic studies of Engler (1878) and Engler and Krause (1908).
The genus Rhodospatha comprises 75 species (T. Croat, unpubl. data) and can be characterized by its generally membranous, oblong to oblong-elliptic leaf with usually closely spaced and prominent primary lateral veins, a prominently canaliculate petiole which is geniculate at the apex. In addition, the ovary has multiple ovules per locule with axial placentation and round to reniform, strongly flattened seeds (Mayo et al., 1997). Rhodospatha is distributed from Mexico to eastern Brazil (Govaerts et al., 2002). In Brazil, the genus has a disjunct distribution between the Amazon and the Atlantic regions, being absent from Central Brazil (Coelho et al., In press). Engler (1878) recognized four species from the Brazilian Atlantic Rainforest: Rhodospatha blanda Schott, R. oblongata Poepp. & Endl., R. heliconiifolia Schott, and R. latifolia Poepp. & Endl. However, Rhodospatha blanda has been synonymized with R. oblongata and R. heliconiifolia has been synonymized with R. latifolia (Govaerts et al., 2002).

During studies on the floristic composition of two Atlantic Rainforest remnants from southeastern Minas Gerais, in Rio Doce State Park, and Caratinga Biological Station (Lombardi & Gonçalves, 2000; Gonçalves & Lombardi, 2004), as well as a floristic survey of Araceae (Temponi et al., 2006), a new species of Rhodospatha was discovered and is here presented and compared with similar species from the Atlantic Rainforest.