Extension of the Cryptanthus range in Northeastern Brazil with new findings in the phenotypic variation including changes in the trichome's distribution, thus enhancing the understanding of the Cryptanthus zonatus complex (Bromeliaceae)

In this paper we describe the first occurrences of the genus Cryptanthus in the state of Rio Grande do Norte (RN), establishing a new northern distribution limit for the genus. Additionally, we report the finding of three forms of C. zonatus growing in sympatry within two different localities in Rio Grande do Norte along with the phenotypic variation in this species complex including changes in trichome's distribution. Cryptanthus zonatus is one of the most popular bromeliads due to its banded leaves. Nevertheless, the fact that it exists in two distinct glabrous-leaved forms is not readily accepted by all the authors. Confusion could be attributed to the fact that they were described from cultivated material without any information about provenance. Based on extensive fieldwork and observations we document here that banded leaves can become glabrescent and that green and red-maroon leaves (treated as forms) may occur on the same shoot. Our finding is important for future biogeographic works when considering Bromelioideae genera distribution in Eastern Brazil center of diversification. This leads to a better understand of species delimitation within this poorly known complex and would impact conservation strategies, given that all the species related to C. zonatus are under threat.