Phylogeny of Tillandsia subg. Diaphoranthema (Bromeliaceae) using morphological and molecular characters.

DONADÍO, SABINA, STARR, J.R. , GIUSSANI, LILIANA MÓNICA, POZNER, RAUL

Ohio

Congreso; Botany 2012, the next generation; 2012

ASPT

Tillandsia subg. Diaphoranthema (Tillandsioideae, Bromeliaceae) includes 28 epiphytic species distributed widely from southern North America to central Argentina and Chile. The species of Diaphoranthema are small plants characterised by the presence of very small, reduced flowers that are few in number (ca. 1-10) such that most species are defined not by floral features but by their phyllotaxy, leaf shape, flower number and bract morphology and number. Beyond its highly variable vegetative features, the group is also of evolutionary interest due to the presence of polyembryony, which is rare in Bromeliaceae. In order to clarify relationships within Diaphoranthema and to understand the evolution of polyembryony and vegetative characters within the subgenus, a phylogenetic analysis of all known species using 102 morphological characters and sequences from the plastid matK and the nuclear ETS regions was undertaken. Morphological and molecular data are congruent in suggesting that Diaphoranthema is monophyletic if it includes some species from the closely related subg. Phytarrhiza which can only be distinguished from Diaphoranthema species by petal shape and larger size. Results also suggest that the subgenus can be divided in three major clades that can be recognised by flower number and phyllotaxy. None of the six informal groups previously recognised are monophyletic in this analysis.