a b s t r a c t
A multidisciplinary study, engaging morphological, carpological and molecular data, has
been performed to investigate the genetic relatedness and taxonomic boundaries of the
close species Hedysarum gmelinii, H. setigerum and H. chaiyrakanicum (Fabaceae) with
overlapped distribution areas in southern Siberia. The diagnostic features of these legume
species are analyzed and discussed, including their macro- and micromorphological
characteristics, seed coat ornamentation and inter-simple sequence repeat (ISSR) profiles.
The morphometric features, pod and seed microsculpture traits of H. chaiyrakanicum and
the ISSR patterns of the three species have been determined for the first time. Sprout, leaf,
calyx, corolla, and stem rachis measurements, leaflet indumentum type and ISSR patterns
significantly discriminate H. chaiyrakanicum from the other two species, whereas plant
height, lengths of stem and leaf, and length and width of leaflet show opposite ranges of
variation for H. gmelinii and H. setigerum though none of them is reliable in species
identification. Ornamentation of seed coat and ISSR patterns does not differ significantly in
the species. Therefore, our study supports the separate taxonomic treatment of H.
chaiyrakanicum and the subordination of the cryptic species H. setigerum within H. gmelinii