New Combinations and a New Species in the Brazilian Genus Chaetostoma DC. (Microlicieae: Melastomataceae)

Abstract

Four new combinations in Chaetostoma (C. albiflorum, C. cupressinum, C. selagineum, C. stenocladon,) are proposed, and a new species, Chaetostoma flavum, endemic to the Chapada dos Veadeiros, Goids, Brazil, is described. The new species can be distinguished by its 4-5-locular ovary and antisepalous stamens with prolonged appendages. Chaetostoma DC. is a genus endemic to Brazil comprising 11 species that occur in campo rupestre, campo de altitude, and campo cerrado vegetation in the states of Goids, Distrito Federal, Minas Gerais, with a less considerable representation in Bahia, Rio de Janeiro, Sio Paulo, and Parani. This genus can be distinguished within the tribe Microlicieae, especially with regard to Microlicia D. Don, to which it has the closest affinity, by the combination of the following diagnostic features: carinate, imbricate, and pungent leaves without translucent dots; the mature capsule longer than the hypanthium; and a crown of trichomes around the outward apex of the hypanthium. The distinction between Chaetostoma and Microlicia has been made by Cogniaux (1883, 1891), in the last revision of these genera, on the basis of just one character: the morphology of the stamens, considered equal in both cycles in Chaetostoma and very unequal in Microlicia. This character has proven to be unreliable, and the most striking difference between these genera is in the possession of the crown of trichomes on the hypanthium in all species of Chaetostoma, which is absent in all species of Microlicia. In a recent revision of Chaetostoma (Koschnitzke, 1997), some taxonomic novelties were recognized, and it was found necessary to propose some new combinations and a new species for the genus. Chaetostoma albiflorum (Naudin) Koschnitzke & A. B. Martins, stat. nov. Basionym: Chaetostoma pungens DC. var. albiflorum Naudin, Ann. Sci. Nat. Bot. Sir. 3, 3: 191. 1845. TYPE: Brazil. Minas Gerais: Serra de Carrancas, 1822, A. St-Hilaire s.n. (holotype, P not seen). Chaetostoma pungens DC. var. pallidiflorum Cogniaux, in Martius, F1. Bras. 14: 32. 1883. Syn. nov. TYPE: Brazil. Minas Gerais: Serra de Itatiaia, Mar. 1839, Riedel s.n. [Martii Herbar. Florae Brasil no. 922] (lectotype, selected here, BR; isolectotypes, BM, G, K, W). Chaetostoma cupressinum (D. Don) Koschnitzke & A. B. Martins, comb. nov. Basionym: Microlicia cupressina D. Don, Mem. Wern. Soc. 4: 302. 1823. TYPE: Brazil. Minas Gerais: 6 May 1819, Sellow 1329 (holotype, BM; isotype, BR). Chaetostoma luteum Cogniaux, in Martius, F1. Bras. 14: 589-590. 1888. Syn. nov. TYPE: Brazil. Minas Gerais: Sao Joao del Rey, Serra do Lenheiro, 24 June 1887, Glaziou 16769 (holotype, B destroyed; lectotype, selected here, BR; isolectotypes, C, F, G, K, MO, P, RB). Chaetostoma lutem Cogniaux var. quadrifarium Cogniaux, in A. DeCandolle & C. DeCandolle, Monogr. Phan. 7: 29. 1891. Syn. nov. TYPE: Brazil. Minas Gerais: Sgo Jolo del Rey, Serra do Lenheiro, 24 Jan. 1889, Glaziou 17503 (holotype, BR; isotypes, BR, C, F, G, K, P, R). Chaetostoma trauninense Cogniaux, in A. DeCandolle & C. DeCandolle, Monogr. Phan. 7: 30. 1891. Syn. nov. TYPE: Brazil. Minas Gerais: Sao Joao del Rey, Serra do Lenheiro, 24 June 1887, Glaziou 16769a (lectotype, selected here, BR; isolectotypes, B, C, F, K, RB). Chaetostoma joannae Cogniaux, in A. DeCandolle & C. DeCandolle, Monogr. Phan. 7: 28. 1891. Syn. nov. TYPE: Brazil. Minas Gerais: Serra do Lenheiro, 1889, Glaziou 17504 (lectotype, selected here, BR; isolectotypes, B, BR, C, F, G, K, P). Chaetostoma selagineum (Naudin) Koschnitzke & A. B. Martins, comb. nov. Basionym: Microlicia selaginea Naudin, Ann. Sci. Nat. Bot. Sdr. 3, 3: 188. 1845. TYPE: Brazil. Goids: Chapadao, A. St-Hilaire 550 (holotype, P not seen; isotype, F). Chaetostoma stenocladon (Naudin) Koschnitzke & A. B. Martins, comb. nov. Basionym: Microlicia stenocladon Naudin, Ann. Sci. Nat. Bot. Sdr. 3, 3: 188. 1845. TYPE: Brazil. Goids: Serra dos Pirineus, 17 June 1819, A. St-Hilaire s.n. (holotype, P not seen; isotype, F). NovoN 9: 202-204. 1999. This content downloaded from 157.55.39.173 on Thu, 19 May 2016 05:43:20 UTC All use subject to http://about.jstor.org/terms Volume 9, Number 2 1999 Koschnitzke & Martins Chaetostoma from Brazil 203