Permafrost and the yearly freezing and thawing, break up plant roots and make it impossible for trees and other tall plants to survive on the Arctic tundra. Plant growth in the alpine tundra is also affected by freezing and thawing. Because alpine tundra occurs on mountains, the sloping terrain, exposure to more light, and the lesser amount of moisture available also affect the kinds of plants that grow here.

Despite the harsh conditions, about 1,700 kinds of plants grow on the tundra, including sedges, reindeer mosses, liverworts, and grasses. The 400 varieties of flowers found here add a wide range of colors.

Algae, Fungi, and Lichens

It is generally recognized that algae (AL-jee), fungi (FUHN-jee), and lichens do not fit neatly into the plant category. In this chapter, however, these special organisms will be discussed as if they, too, were plants.

Algae Algae play an important role in...