4b. Lotus corniculatus var. japonicus Regel, Index Sem. Hort. Petrop. 23. 1864.
光叶百脉根 guang ye bai mai gen
Lotus japonicus (Regel) Larsen.
Plants glabrescent or sparsely puberulent on rachis, petiolules, midrib, calyces (especially on teeth margins and abaxial part of tube), and sometimes stems. Umbels 1-3(or 4)-flowered. Flowers 10-12.5(-14) mm. Corolla yellow. Calyx teeth slightly longer than tube, sometimes equaling it, narrow part of 2 upper calyx teeth less than half their length. 2n = 12.
Grasslands, ravine slopes, mountain meadows, alongside irrigation channels and streams, rice fields, river valleys, lake banks, roadsides, rocky slopes; below 3100 m. Provinces of upper and middle Chang Jiang, C, NW, and SW China, Taiwan [Japan, Kashmir, Korea, C and W Nepal].
In FRPS (42(2): 224, 226. 1998), Lotus alpinus (Seringe) Schleicher ex Ramond (Mem. Mus. Hist. Nat. (Paris) 13: 275. 1825; L. corniculatus var. alpinus Seringe in Candolle, Prodr. 2: 214. 1825) was recorded from alpine rocky slopes at 3000-3500 m in Qinghai and Xizang. One of us (Kramina) has seen no specimens similar to L. alpinus among the material studied from China. Probably some mountain forms or varieties of L. corniculatus sensu lato exist in China, but these do not seem close to those from C Europe or even Turkey, where L. alpinus is otherwise distributed. This problem needs additional study using both morphological and molecular-genetic methods.