A grass with very tall, hollow stems. Long, flat leaves spread out widely from the stem, growing 4 to 20 inches long and 1 to 1½ inches wide, with rough edges and a fine tip. The leaf collar, or ligule, a small outgrowth where the stem and leaf join, is a ring with dense, stiff hairs. Tawny, purplish flowers have long, silky hairs and occur in a large, plumelike panicle 6 to 20 inches long. Blooms in midsummer; seed set by late September.