Phylogenetic relationships and critical taxonomic notes on the genus Astragalus (Fabaceae) in Kazakhstan (Central Asia): Part I

In the case of many previously described Astragalus species, more than 3,100 species worldwide, particularly those that are endemic and rare, there is a lack of critical information, such as wild photo illustrations, taxonomic notes, and genetic resources. We investigated the taxonomic status and phylogenetic relationships of 26 Astragalus species including 3 endemics to Kazakhstan, using samples collected in 2025 to address this gap.

We sequenced the internal transcribed spacer (ITS) of all studied Astragalus species. In the phylogenetic tree, all Astragalus species were monophyletic and had the same topology as reported in previous studies. Our phylogenetic tree was divided into two primary clades.

Clade I included species of the subgenera Calycophysa and Caprinus, whereas Clade II included species of the subgenera Cercidothrix and Trimeniaeus. In Clade I, each section was well-separated from the others, except for the sections Chaetodon, Erioceras, and Dissitiflori in the subg. Cercidothrix.

The taxonomic positions of some Astragalus species, based on morphological and molecular evidence, are also discussed. The detailed illustrations and species documentation presented in this study will serve as significant references for future taxonomic and identification studies of this genus.