Astragalus taiyuanensis was newly found,which was only located in Shanxi and Shaanxi Province of China.Floral organogenesis and development in A.taiyuanensis were studied by means of scanning electron microscopy.Results were as followed:(1)sepals,petals,outer stamens,and inner stamens were formed unidirectionally in each whorl from the abaxial to the adaxial sides of the flower.Overlap in starting time between members of adjacent whorls occured.(2)The existence of two forms of common primordia,categorized as primary and secondary,was observed.Primary common primordia develop into antesepalous stamens and secondary common primordia.In comparison,the five secondary common primordia subdivide into a petal and an antepetalous stamen primordia respectively.(3)Filament tube had two adaxial fenestrations at base,which was adaptation to the pollinators and in favor of pollination activities.(4)Ovules were anatropous and bitegmic in A.taiyuanensis.Anatropous ovules was a result of the appearance of both inner and outer integuments.