Tundra is widespread in the Arctic north of the tree lines of North America and Eurasia, but occurs in only scattered localities on Antarctic islands, where is consists mainly of lichens and mosses.

• 在北极圈、北美洲林木线以北和欧亚大陆均广泛分布有苔原。而在南极洲仅有零散分布，由青苔和苔藓类组成的苔原。