Senna Mil. (Leguminosae-Caesalpinioideae) in Minas Gerais state, Brazil

• Ano de defesa: 2017
• Autor(a) principal: Oliveira, Leticia das Graças Rosignoli de
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Universidade Federal de Viçosa
• Palavras-chave em Português: Senna - Taxonomia - Minas Gerais; Angiosperma; Botânica
• Link de acesso: http://www.locus.ufv.br/handle/123456789/10620

Senna Mill. is a genus characterized by pinnate leaves, the absence of bracteoles, pentamerous flowers and in general, yellow, and heteromorphic androecium. It was segregated from Cassia L. and actually has 295-350 species worldwide, 80 from Brazil. In Minas Gerais a preliminary survey indicated the occurrence of 75 species names, 351 unidentified specimens and 39 species were identified in Flora do Brasil. This study aims to update the identifications of the collections and delimit the circumscription of Senna species found in the State of Minas Gerais. This research was based on the morphological analysis of about 2350 specimens from both herbaria and field collections. The collected materials were deposited in the Herbarium VIC and the identification of the materials was performed by taxonomic literature for the genus. The occurrence and distribution data of this species was collected in the labels of specimens deposited in herbaria and taxonomic studies. The ArcGis software was used for the maps of the geographical distribution. It was recognized 36 species were recognized, being 34 native, 2 cultivated and 28 varieties. Chamaefistula (Collad.) Irwin & Barneby is the section more represented in the State, with 10 series and 28 species, followed by sect. Peiranisia (Raf.) Irwin & Barneby with 2 series and 5 species and S. sect. Senna Mill with 2 series and 3 species. Among the species cited in the literature as occurring in Minas Gerais, in this study, Senna acuruensis (Benth.) Irwin & Barneby was included and 4 species were excluded of the list: Senna spinigera (Rizzini) Irwin & Barneby, Senna bacillaris (Lf) Irwin & Barneby, Senna chrysocarpa (Desv.) Irwin & Barneby and Senna trachypus (Benth.) Irwin & Barneby. About Senna spinigera, specimens collected in the State were not indicated. The materials identified as Senna bacillaris (L.f) Irwin & Barneby were reidentified as Senna affinis. Five specimens identified by Senna chrysocarpa (Desv.) Irwin & Barneby were reidentified as Senna velutina (Irwin & Barneby), Senna rugosa (G.Don) Irwin & Barneby and Senna reniformis (G. Don) Irwin & Barneby and the identified materials As Senna trachypus were reidentified as Senna oblongifolia (Vogel) Irwin & Barneby. After updating these specimens, no other specimens of these species were found for the State. Senna pilifera (Vogel) Irwin & Barneby var. tubata Irwin & Barneby is a new registry for the state of Minas Gerais, the occurrence of Senna acuruensis (Benth.) Irwin & Barneby in the State is confirmed in this study, where its occurrence was considered a possibility in the review study about the genus. Senna hirsuta (L.) Irwin & Barneby var. acuminata (Benth.) Irwin & Barneby is endemic to the state. Among the species and varieties found in this study, 36% are endemic to Brazil, 26% occur in up to three States, 48% in up to 10 States, and 26% are cited for more than 11 brazilian States. Senna has great diversity in the biomes occurring in Minas Gerais, with 28 spp in the Cerrado, 26 spp in the Atlantic Forest and 20 spp in the Caatinga. The Atlantic Forest has 8 taxa that are considered restricted to its area of occurrence: Senna angulata (Vogel) Irwin & Barneby var. miscadenia (Vogel) Irwin & Barneby, Senna itatiaiae Irwin & Barneby, S. neglecta (Vogel) Irwin & Barneby var. neglecta and S. neglecta (Vogel) Irwin & Barneby var. oligophylla (Benth.) Irwin & Barneby, Senna organensis (Harms) Irwin & Barneby var. organensis, Senna pneumatica Irwin & Barneby, Senna tenuifolia (Vogel) Irwin & Barneby and Senna tropica (Vell.) Irwin & Barneby. For the Cerrado, S. hirsuta var. acuminata and S. rostrata (Mart.) Irwin & Barneby are considered of restricted occurrence to this Biome and, for the Caatinga, only S. acuruensis was found. Senna pentagonia (Mill.) Irwin & Barneby var. pentagonia had its occurrence extended to the Atlantic Forest Biome, since it was mentioned in the literature only for the Caatinga and the Cerrado. The data demonstrates the richness of the flora of State and the importance of its conservation. Identification key, descriptions, illustrations, taxonomic comments and geographical distribution are provided for this species.