Biosystematic studies on Borreria subsect. Latifoliae (K. Schum.) Bacigalupo & Cabral (Spermacoceae, Rubiaceae).

SANDRA V. SOBRADO; ELSA L. CABRAL

Salvador, Bahía

Conferencia; VI International Rubiaceae & Gentianales Conference; 2014

Comité Organizador de VI International Rubiaceae & Gentianales Conference

Biosystematic studies on Borreria subsect. Latifoliae (K. Schum.) Bacigalupo & Cabral (Spermacoceae, Rubiaceae) Sandra V. Sobrado (1); Elsa L. Cabral (1) (1) Instituto de Botánica del Nordeste (IBONE). Universidad Nacional del Nordeste. Corrientes, Argentina. E-mail de contacto: sobradosandra@gmail.com Borreria subsect. Latifoliae comprises about 18 American herbs, subshrubs and scandents species. These species are distributed from Mexico to Argentina and grow mainly in gramineous fields with lateritic soils. These species present capsules with longitudinal dehiscence, exserted stamens and style, and a bifid stigma. Nine species of this group are endemic from campos rupestres of Minas Gerais and Rio do Janeiro and Amazonian forest of Pará, Brazil. The taxonomic studies resulted in the description of seven new taxa, new combinations and synonyms proposed and expanded known geographical areas. We also proposed a taxonomic differentiation between two taxa commonly confused, B. alata and B. latifolia. Morphological and palynological analysis and chromosome data are present for the first time in some taxa. Some species of this group display a peculiar and unusual stamen organization, phenomenon scarcely documented in Spermacoceae and even in Rubiaceae. The pollen morphological study revealed uniformity in form, sculpture and structure of the pollen in most of the taxa. Thought, an endoaperture was observed as an endocingulum. The chromosome numbers are consistent with the basic number reported for the tribe Spermacoceae (x=14), to which we add a new basic number for two species of this group.