Black Medick (Medicago lupulina, 天蓝苜蓿).
A plant with many English names. The name medicago is based on the ancient Greek belief that alfalfa plants came from the Mede kingdom, now a part of Iran. Seeing its hops as 'wolf-like', lupulina, requires some imagination. In any case, it is now in flower on Yuelu Mountain, much to the delight of the bees.
