Contributions to taxonomy, palynology and seed micromorphology in Borreria subsect. Borreria of South America

MIGUEL, L.M.; CABRAL, E.L.

Salvador Bahia

Congreso; VI International Rubiaceae and Gentianales Conference; 2014

VI International Rubiaceae and Gentianales Conference

Borreria G. Mey. belongs to tribe Spermacoceae and includes 100 species in Americas. For its morphological similarity with Spermacoce L., the generic status of Borreria has been the subject of debate. The African, Australian and Asian species of Borreria were relegated as synonyms of Spermacoce. Although, for the American taxa we consider maintained both genera. In our opinion, Borreria subsect. Borreria should not be relegated to synonyms of Spermacoce. This subsection includes ca. 50 species and is distinguished by bilateral glomerules, exserted stamens and styles, and capsular fruits with both mericarps dehiscing septicidally from the apex. This work reports preliminary results on the revision of South American Borreria subsect. Borreria species. We present descriptions and comments related to taxonomy and geographic distribution for each species. In order to contribute to the identity of this group, we studied pollen of 14 species, 9 of which are analyzed for the first time, and the analyses of the internal surface are added. Also, we studied micromorphology seeds of 30 species and the results do not support the division of the subsection in series. As results to the taxonomic revision, we clarify the identity of Borreria valens, B. scabiosoides and B.linoides, reinstate B. spinosa and B. virgata, and describe seven new species for South America. Also, we designate a lectotype for B. humifusa, a neotype for B. virgata, an epitype for B. scabiosoides, and new synonyms for B. verticillata and B. scabiosoides.