In China, the locoweeds are mainly distributed in the
northwestern and northern regions including Inner
Mongolia, Gansu, Ningxia, Qinghai, Xinjiang, Tibet,
and Shanxi. According to preliminary surveys (Liu
et al. 2010), the area of locoweed infestation in
China exceeds 110 million hectares, which accounts
for about 2.8 percent of the total grassland area in
this northern region. It is reported that 45 species of
locoweeds (22 species of Oxytropis and 23 species
of Astragalus) occur in China (Huang et al. 2003).
Of these, eight species of Oxytropis and three
species of Astragalus contain swainsonine (table 1).