Comparative floral ontogeny in Adesmia (Leguminosae: Papilionoideae: Dalbergieae)

Floral organogenesis of six Brazilian species of Adesmia DC. was studied by scanning electron microscopy. Considering the number of species, this is the most comprehensive organogenetic study of a genus conducted. A unidirectional sepal formation from the adaxial towards the abaxial side of the floral meristem is shown for the first time in the subfamily Papilionoideae. This pattern was found in all studied taxa except for A. latifolia in which the five sepal primordia are formed simultaneously. The present study suggests that the ontogenetic. oral differences among Adesmia species may be useful in a re-evaluation of infrageneric categories and for future systematic analyses.