A multidisciplinary study of Diodia s.l. (Spermacoceae-Rubiaceae)

ANDREA A. CABAÑA FADER; BEATRIZ GALATI; ROBERTO M. SALAS; ELSA L. CABRAL

San Salvador, Bahia

Conferencia; VI Conferência International de Rubiaceae e Gentianales (VI International Rubiaceae and Gentianales Conference); 2014

HUEFS

Diodia is one of the most conflictive genus belonging to the Spermacoce clade. For decades,this taxon consisted in species with indehiscent fruits and/or schizocarpic fruits, though with remarkable morphological variations. It results in a polyphyletic group with approximately 120 species. Whence, the terminology Diodia s. l. is referred to an artificial group of taxa, which include the five species of Diodia s.s and all species that were described in Diodia or ever were related to this taxon. The aim of this work is to establish the taxonomic status of the entities and determine possible phylogenetic relationships. We analyzed cytogenetic, morpho-anatomical palynological, and embryological characters of species principally from Americas, joined with the taxonomic studies the most conflictive and less studied taxa of Diodia s.l. Among the most important results of this work, we were updated the names of 30 species and were established new taxonomic arrangements in the group, with a strong support of the pollen and seed morphology. The embryological and cytogenetic analysis yielded very promising results to the taxonomy of Diodia group and other nearby taxa of the Spermacoce group. Moreover, the fruit was reaffirmed as a character of importance only in some species of the group.