Taxonomy and floristic geographical distribution of the Chinese medicinal Huangqi

It is indicted definitely that the Chinese medicinal Huangqi plants have 3 species——Astragalus membranaceus(Fisch.) Bunge,A.mongholicus Bunge and A.brealimongolicus Y.Z.Zhao which is a new species;It is defined the floristic geographical elements of the 3 species: A.membranaceus is distributional species of the forest zone of northern east Asia-southern Siberia,A.mongholicus is distributional species of the forest-steppe zone of northern China,A.borealimongolicus is distributional species of steppe zone of northern Mongol Plateau; It is found that 3 species form obvious distribution pattern of geographical substitute.