Phylogenetic analysis of the subtribe Chloraeinae (Orchidaceae): a preliminary approach based on three chloroplast markers

CHEMISQUY, M. A.; MORRONE, O.

AUSTRALIAN SYSTEMATIC BOTANY

CSIRO PUBLISHING

Año: 2010 vol. 23 p. 38 - 46

1030-1887

The systematic position and relationships between some South American terrestrial orchids, such as Bipinnula, Chloraea, Gavilea and Geoblasta,  is unclear. These four genera have been grouped in the subtribe Chloraeinae by several authors and under the tribes Diurideae, Geoblasteae, Spirantheae and Cranichideae by others. Besides, some authors have raised the subtribe Chloraeinae to the tribe level. Previous phylogenetic studies of the group have only included a few species of Chloraea and Gavilea and not of Bipinnula or Geoblasta. Therefore, the monophyly of Chloraeinae should be tested, and the phylogeny of Bipinnula, Chloraea, Geoblasta and Gavilea needs to be explored. For the molecular phylogenetic analyses, three chloroplast markers were used: the matK-trnK intron, the atpB-rbcL spacer and the rpoC1 gene. Sequences were analyzed under Maximum Parsimony and Bayesian inference. In all the analyses Bipinnula, Chloraea, Gavilea and Geoblasta were grouped in a clade with high support, where Bipinnula, Geoblasta and Gavilea were nested inside Chloraea. Consequently, Chloraea was paraphyletic, while Gavilea  turned out to be monophyletic with high values of support. The Cranichideae species appeared as a sister group of the Chloraeinae. A more exhaustive taxonomic sampling is needed to solve the systematic placement of the subtribe Chloraeinae and the internal relationships between the genera and species that form it.