There are numerous grasses and sedges in the fescue prairie. Prior to 2002 a combination of 70% ryegrass and 30% Creeping Red Fescue was used. Tall fescue is a long-lived perennial bunchgrass species. All lava flows support patches of grasses such as Idaho fescue, especially on north-facing slopes. Pure grasslands dominate lower elevations, with bluebunch wheatgrass, Idaho fescue, and Sandberg bluegrass. Festuca ovina, sheep's fescue or sheep fescue, is a species of grass. Common names include blue fescue, blue mountain grass, and grey fescue. Festuca californica is a species of grass known by the common name California fescue. The hills and uplands are covered with Idaho fescue, bluebunch wheatgrass, and Sandberg bluegrass. Other plant life includes wormwood, knotweed, fescue and nettle. A symbiotic fungus in fescue may cause illness in horses and cattle. Fescue pollen is a significant contributor to hay fever. In the winter, a condition known as "fescue foot" might afflict cattle. It is dominated by communities of Altai fescue and lichen. It is sometimes confused with hard fescue ("Festuca trachyphylla").