Vegetative axis anatomy of Dahlstedtia pinnata (Benth.) Malme and D. pentaphylla (Taub.) Burk. (Leguminosae, Papilionoideae)

Abstract

Dahlstedtia Malme is a Neotropical genus, native to the Brazilian Atlantic forest, with two species. It is considered monotypic by many authors. The comparative anatomy of the vegetative axis was studied in order to verify the presence of anatomical characters that can help in the species delimitation. In spite of the anatomical similarity between species, some distinctive characters were found, like the presence of crystalliferous idioblasts in the secondary phloem of D. pentaphylla stem, a smaller number of primary stem fibre layers in D. pinnata, and the region of the secretory cavities origin in the shoot apex. As some differences were quantitative, they must be carefully used in species taxonomic delimitation.