The seed coat patterns of 18 species (3 populations) of Hedysarum L. from China were examined under scanning electron microscope. Survey results revealed that seed coat patterns have important taxonomic significance at the species level, thus, the patterns were proposed as an attribute for taxonomical study of Hedysarum Two types of patterns, including smooth and coarse, and five sub-types, including favulariate, ruminate, areolate, reticulate and finely reticulate, were recognized on the basis of their microsculpturing features. These pattern types reflect evolutionary trends from the favulariate through the finely reticulate to the present smooth type, which verifies that seed coat patterns play an important role in Hedysarum phylogeny. Not all species of Hedysarum were investigated here, and others may display different testa patterns. Therefore, the present study was limited for Hedysarum phylogeny study.
Hongliang et al. (Sat,) studied this question.