In order to characterize the embryonic axes of seeds of Fabaceae and to provide information about the systematics and phylogeny of this family, morphological and anatomical aspects of embryos were studied, especially embryonic axes of 15 native tree species in an attempt to correlate axis structures and affinity among genera, as well as genera in tribes. Foliaceous cotyledons in Caesalpinioideae, fleshy cotyledons in Faboideae, and foliaceous and fleshy cotyledons in Mimosoideae were observed. The embryonic axes ranged from short to long, being straight in Caesalpinioideae and Mimosoideae, and curved or deflexed in Faboideae. The plumules ranged from undifferentiated to differentiated. The undifferentiated plumules were found in species with no epicotyl, while differentiated plumules were arranged on the elongated epicotyl. The anatomy of the protoderm was undifferentiated in most species. Trichomes in differentiation were seen in Caesalpinia leiostachya, Centrolobium tomentosum and Anadenanthera macrocarpa, papillae in Platypodium elegans, and differentiated glandular and non-glandular trichomes in Inga urugüensis. The procambium was undifferentiated. The ground meristem showed starch accumulations in all the species. Druses were seen in Peltophorum dubium, and isolated polyhedral crystals in Inga urugüensis and in Lonchocarpus muehlbergianus. This latter species also showed secretory structures in the cotyledon node region.
Fabaceae; Leguminosae; plumule; embryonic axis