Species in the genus Astragalus:

Astragalus sinicus / Rengesou ゲンゲ syn.  レンゲソウ

Astragalus sinicus is a biennial herb originating in China. Stems expand, creeping on the ground, growing to 10-25cm in height. Leaves are of an imparipinnate compound leaf; the leaflets are 7-11 in number, 0.8-1.5cm in length, in the shape of an obovate or oblong. Flowers measure approximately 1.5cm long and put themselves on tips of flower stalks in a whorl of 7-10 purple flowers. Bloom time: April-June.