The vegetation of ANWR is characterized as tundra, which literally means barren land. Yet, contradictory to its name, there is much diversity in the types of plants growing in ANWR. The tundra plants are usually less than 1 foot high. Tall plants are restricted to the southern slopes of ANWR. The tundra plants belong to five main groups, namely, 1) lichens, 2) mosses, 3) grasses and grass-like herbs including many sedges and willows, 4) cushion plants and 5) dwarf shrubs. (Patrick D. Baird, 1964) Among them, the first three types are particularly important in providing the herbivores with nutrition and calving ground, nutrient cycle, maintainence of permafrost and a lot more essential functions in the arctic ecosystem. Sedges, willows, mosses and lichens would be discussed in greater details.