Revisitando as Asclepiadoideae (Apocynaceae) da Cadeia do Espinhaço (original) (raw)

2010, Boletim de Botânica

Revisiting the Asclepiadoideae (Apocynaceae) from the Espinhaço Range)]. A survey of the Asclepiadoideae (Apocynaceae) from the Espinhaço Range is presented. Based on the determinations of 3,615 collections, 133 species and 24 genera were recorded for this region; the most diverse genera are Fkvcuuc (30 species), Qz{rgvcnwo"(24),"Okpctkc"(19), Jgokrqiqp"(9), and Ocvgngc (8). Within the Espinhaço Range, 108 species occur in Minas Gerais and 66 species occur in Bahia; 41 (ec0 30%) of these species are found in both states. Fortytwo (ec0 30%) species are endemic to the Espinhaço Range, which are mostly found in the Serra do Cipó and Diamantina Plateau, in Minas Gerais, and Chapada Diamantina, in Bahia. The sampling effort in Bahia is nearly half of that in Minas Gerais. As seen with Minas Gerais, this suggests that collecting more in Bahia will lead to the discovery of new taxa and to a better understanding of the distribution ranges of known species. In comparison with a survey published almost 10 years ago, for the Minas Gerais section of the Espinhaço Range, the classifi cation of nearly 20% of the species has changed; most of these changes were based on phylogenetic studies. As a consequence, these studies about the Asclepiadoideae are revealing lineages that evolved predominantly in the Espinhaço Range, such as Okpctkc"and Jgokrqiqp. They also indicate that cladogenesis events might have been more frequent in the Espinhaço Range of Minas Gerais compared to the section in Bahia or, alternatively, extinctions events have been rarer in the Minas Gerais section. This pattern suggests that environmental factors are directly involved in the diversifi cation of these plants along the Espinhaço Range and that comparative studies between the two sections of this range may reveal the principal causes associated with the rise of microendemics.