Estudos anatômicos e taxonômicos da subtribo Sipolisiinae H.Rob. (Asteraceae Martinov)

Abstract

The Asteraceae (Compositae) is the largest angiosperm family with 43 tribes, 1.600-2.000 genera and 24.000-30.000 species, distributed around the globe except for Antarctica. The tribe Vernonieae has undergone changes in its classification, since the largest genera of the tribe, Vernonia Schreb, was segregated in several others, and several subtribes were created. The subtribe Sipolisiinae is characterized by its receptacle with pales or spines and cypsela usually with phytomelanin, and contains the genera Heterocoma DC., Bishopalea H. Rob, Sipolisia Glaz. ex Oliv., Xerxes J. R. Grant e Hololepis DC. The monophyletism of this subtribe has been questioned since it was created. With a new proposal of classification Hololepis is excluded from the subtribe, and all genera are synonymized under Heterocoma. To evaluate this proposed classification of the subtribe, anatomic and taxonomic studies were carried out. Through the foliar and cypsela anatomy, these proposal was confirmed, once no anatomic character justify the recognition of the genera. Besides, the genus Hololepis presented several anatomic characters which differentiates it from others notably the lack of phytomelanin in the cypsela. Based on this proposal of classification, the taxonomic study confirms the anatomic analysis, since there are no relevant morphological characters reliable to clearly support any taxa at the generic level. In this study is provided a key for the seven species recognized in Heterocoma, and a description of a new specie Heterocoma semiriana F. S. Freitas & J. N. Nakajima.