Espinhaco Range Research Articles

Tecomeae (Bignoniaceae) da Cadeia do Espinhaço, Minas Gerais e Bahia, Brasil

Este trabalho consiste num levantamento florístico dos representantes da tribo Tecomeae (Bignoniaceae) ocorrentes na Cadeia do Espinhaço, região serrana do interior de Minas Gerais e Bahia com cobertura vegetal constituída principalmente por campos rupestres. A tribo está representada na área por 17 espécies, distribuídas em 4 gêneros: Zeyheria (2 spp.), Tabebuia (6 spp.),Jacaranda (8 spp.) e Cybistax (1 sp.). São apresentadas chaves para os gêneros e espécies, descrições, ilustrações e comentários. J. oxyphylla é considerada sinônimo de J. caroba e J. morii é considerada sinônimo de J. ulei.

Two new species of Vellozia (Velloziaceae) from Minas Gerais, Brazil

Two new species of Vellozia from the Espinhaco range in the State of Minas Gerais, Brazil, are described and their taxonomic relationships are considered. A discussion of their geographical distribution and an account of their leaf anatomy is provided.

A New Species of Vellozia from the Espinhaco Range, Brazil, with Some Considerations on the Section Xerophytoides

The genus Vellozia Vand. consists of approximately 150 species; these are divided into 3 Sections: Vellozia, Radia and Xerophytoides (Smith & Ayensu 1976), primarily Brazilian in their distribution. The genus is particularly wellrepresented in the "campo rupestre" vegetation of Brazil, where it has achieved its maximum in terms of genetic diversity. Recent collections by the author and colleagues in the northern part of the State of Minas Gerais, during the course of field work for a floristic study of the vegetation of the Gr~io-Mogol region, have revealed 3 new species of Velloziaceae. Two of these have already been described (Mello-Silva & Menezes 1988). The third, V. prolifera, is endemic to the region. It is peculiar in that it increases vegetatively by elongation of the branches; the fact of its having 12 stamens involves modification of the circumscription of Section Xerophytoides, in which it should be included.

ESTUDO DA DEFORMAÇÃO EM METAVULCANITOS ÁCIDOS DA SERRA DO SAPO, CORDILHEIRA DO ESPINHAÇO MERIDIONAL, MG

The region of Conceicao do Mato Dentro and Serro is characterized by the presence of polydeformed porphyritic metarhyolites and metarhyodacites wich are imbricated within the tectonic framework of the Southern Espinhaco Range. In these occur a sub parallel mylonitic foliation and an intense estretching lineation. The non-coaxial aspect of the deformation is distinguished by the generalized assymetry of some deformed elements(fi.e., the assymetric pressure shadows and the S-C structural planes). Such structural features permit the assumption of crustal shearing responsable for the ridge structure.

ESTUDO DA DEFORMAÇÃO EM METAVULCANITOS ÁCIDOS DA SERRA DO SAPO, CORDILHEIRA DO ESPINHAÇO MERIDIONAL, MG

The region of Conceição do Mato Dentro and Serro is characterized by the presence of polydeformed porphyritic metarhyolites and metarhyodacites wich are imbricated within the tectonic framework of the Southern Espinhaco Range. In these occur a sub parallel mylonitic foliation and an intense estretching lineation. The non-coaxial aspect of the deformation is distinguished by the generalized assymetry of some deformed elements(fi.e., the assymetric pressure shadows and the S-C structural planes). Such structural features permit the assumption of crustal shearing responsable for the ridge structure.

Duas espécies novas de Velloziaceae de Minas Gerais

Duas novas especies brasileiras de Velloziaceae são descritas: Pleurostima riparia N. Menezes & Mello-Silva, conhecida somente de Grão-Mogol e Vellozia luteola Mello-Silva & N. Menezes, de Grao-Mogol e Itacambira, ambas do campo rupestre da Cadeia do Espinhaço, ao norte de Minas Gerais. São apresentadas descrições incluindo características morfológicas das partes vegetativas e florais e características anatômicas das folhas, além de ilustrações do hábito, flores e frutos. Também são discutidos os atributos característicos de cada espécie, assim como suas relações com táxons afins

Essai sur la tectonique de la region a l'est de Belo Horizonte, Minas Gerais, Bresil

Abstract The Espinhaco range east of Belo Horizonte, Minas Gerais Brazil, is not a folded massif, but a monoclinal structure whose formation was caused by large-scale tilting, accompanied by differential dislocation of the Precambrian components of the terrain and local overthrusting due to compression and by later tension fracturing. The orogenic activity is considered to have taken place subsequent to deposition of Tertiary (Miocene?) sediments in two small lacustrine basins in the region, which exhibit the same style of dislocation as the older strata of the range.