Updating the list of chromosome numbers for Philodendron (Araceae)

Abstract

Aiming for a better understanding of karyotype evolution within Philodendron, we report chromosome counts for 23 species of the genus, of which 19 are being reported for the first time, thus increasing to 84 (ca. 17 % of the genus) the total number of species with available chromosome counts. The diploid numbers 2n = 32 and 2n = 34 were the most common, with 10 and 11 species, respectively, whereas only two species presented different chromosome numbers (P. giganteum with 2n = 30 and P. adamantinum with 2n = 36). The results are discussed in the context of previous analyses of karyotypes of Philodendron spp., taking into account bidirectional dysploidy as the main mechanism of chromosome number evolution within the genus.