(formerly Trichophorum), a genus of plants of the family Cyperaceae. The plants are perennial herbs that often form thick covers. The leaf blades are short and bristlelike. The bisexual flowers are usually in solitary apical spikelets; the spikelets are few-flowered. The perianth has six bristles or six hairs, which greatly increase in length after flowering; sometimes the perianth lacks both bristles and hairs. The nutlike fruit is usually triquetrous.
There are about ten species, which are distributed in the cold and temperate belts of the northern hemisphere and the high-mountain regions of the subtropics and tropics of Asia. The USSR has four species, growing in the arctic and mountain tundra and in the forest zone. The most common species are deerhair (B. caespitosum) and B. alpinum, both of which grow in mossy swamps. In the tundra the plants serve as food for deer in the early spring and when snow covers the ground.