Abstract

Chaetanthera is an exclusively South American genus comprising 42 species approximately. Although being a genus taxonomically well-studied, there are discrepancies with the evolutionary studies that have been made about it. The most recent taxonomic study of Chaethanthera was published by Cabrera in 1937 recognizing seven subgenera, based on the habit and involucre bracts characteristics. However, in the only phylogenetic study about the genus, these groups are paraphyletic. In the present work, karyotypical characteristics of Chaetanthera moenchioides are given and comparisons with other five species of Chaetanthera are done. The results are discussed from taxonomic and evolutionary perspective. Although preliminary, karyotypical evidence is congruent with the phylogenetic results corroborating to Chaetanthera as a paraphyletic subgenus and indicating that changes in the karyotype of Chaetanthera would occurred with decrease in chromosome number. On the other hand, there could be a decrease of the length of total genome and an increase of asymmetric karyotypes in species that are growing in high altitude.