Seed Coat Surface Patterns and Structures of Oxytropis riparia, Oxytropis campestris, Medicago sativa, and Astragalus cicer

Scanning electron microscopy was used to examine external and internal seed coat structures of Oxytropis riparia Litv., Oxytropis campestris L., Medicago sativa L., and Astragalus cicer L. for characteristics useful in taxonomic classification and to identify hard seed coat components which affect permeability. Seed coat surfaces of the four species were distinctly different. Palisade and hourglass cell lengths and parenchyma and endosperm cell layer thicknesses were similar among species with the exception of O. campestris seeds which lacked an identifiable endosperm layer. Surface pattern differences and the presence of a distinct endosperm layer are useful in separating these genera and species. Cellular and morphological differences were not observed between hard and non-hard seed coat structures. The rugulate surface pattern of O. riparia, the lophate surface pattern of O. campestris, and the internal seed coat structures of both species have not been reported previously