The Qinling or Qin Mountains, formerly known as the Nanshan, are a major east–west mountain range in southern Shaanxi Province, China. The mountains mark the divide between the drainage basins of the Yangtze and Yellow River systems, providing a natural boundary between North and South China and support a huge variety of plant and wildlife, some of which is found nowhere else on earth.

Physochlaina is a small genus of herbaceous perennial flowering plants belonging to the nightshade family, Solanaceae, found principally in the north-western provinces of China although one species occurs in Western Asia, while another is found as far east as those regions of Siberia abutting the eastern borders of Mongolia and, furthermore, not only in Mongolia itself, but also in the Chinese autonomous region of Inner Mongolia. Some sources maintain that the widespread species P. physaloides is found also in Japan, but the species is not recorded as being native in one of the few English-language floras of the country. The genus is a valuable one, since its species are not only of considerable medicinal value, being rich in tropane alkaloids, but also of ornamental value, three species having been grown for the purpose, although hitherto infrequently outside botanical gardens. Furthermore, the genus contains a species formerly used as an entheogen in Siberia.