Taxonomia de Croton sect. Ocalia (Klotzsch) Baill. no Brasil e Croton sect. Geiseleria (A. Gray) Baill. s.l. (Euphorbiaceae) no Nordeste do Brasil

Abstract

The genus Croton comprehends approximately 1.200 pantropical species, distributed predominantly in America, with greater diversity in Brazil. Presents a wide distribution, morphological variation and tipification problems. This study investigated the taxonomy of Croton sect. Ocalia (Klotzsch) Baill sect. Ocalia sensu Webster (1993) occurred in Brazil, despite its recently synonymized to C. sect. Geiseleria (A. Gray) Baill. made by Van Ee et al. (2011) for the Brazil’s Northeast to improve the understanding of this new circumscription. The data were based on morphological analysis of specimens from herbarium: ALCB, BHCB, CEN, CH, EAC, ESA, FLOR, FURB, HEPH, HST, HUCS, HUEFS, IAC, IBGE, ICN, INPA, IPA, OUPR, PAMG, PEUFR, R, RB, SP, SPF, SPSF, TEPB, UB, UCS, UEC, UFG, and material collected in areas of Caatinga and Cerrado in northeast and midwest Brazil. In addition, were analyzed photographs of type material and original descriptions. Is presented a taxonomic study, including an identification key, descriptions, comments about distribution and phenology for Brazilian species of C. sect. Ocalia (Klotzsch) Baill. C. antisyphiliticus Mart., C. glechomifolius Müll. Arg., C. goyazensis Müll. Arg., C. inaequilobus Steyerm., C. junceus Baill., C. mucronifolius Müll. Arg., C. nepetifolius Baill., C. tetradenius Baill., and a lectotipication for C. junceus. This groups was defined for shrubby habit, stellate trichomes, presence of glands on apex of petiole or base of leaves, usually double-serrated or serrated, inflorescence usually continuous, petals absent in pistillate flowers and seeds without a marbled mottled. For Croton sect. Geiseleria s.l. in northeastern Brazil, were recorded 14 species that occur mainly in open areas of the Caatinga and Cerrado: C. adamantinus Müll. Arg., C. agoensis Baill., C. antisyphiliticus Mart., C. glandulosus L., C. goyazensis Müll. Arg., C. grewioides Baill., C. hirtus L’Her., C. lundianus (Didr.) Müll. Arg., C. mucronifolius Müll. Arg., C. nepetifolius Baill., C. sincorensis Mart. ex Müll. Arg., C. tetradenius Baill., C. trinitatis Millsp., C.virgultosus Müll. Arg. Identification key, comments of distribution and illustrations with diagnostics features of species are presented.