Poa mannii of the Poaceae (grass) family is a perennial with short rhizomes (underground stems) and erect, tufted culms (bunched stems) 50 75 cm (20 to 30 in) tall. The leaf sheath completely surrounds the leaf, and the ligule (appendage at the junction of the leaf blade and sheath) completely encircles the stem, is about 0.5 mm (0.02 in) long, and has a tooth about 2 to 4 mm (0.08 to 0.2 in) long and a fringed margin. The leaf blade is up to 15 cm (6 in) long and 2 to 4 mm (0.08 to 0.2 in) wide and has a rough upper surface and a hairless lower surface. The panicles (branched flower clusters) are usually less than 5 cm (2 in) long and have primary branches 5 to 20 mm (0.2 to 0.8 in) long. The 4 to 7 mm (0.2 to 0.3 in) long, flattened spikelets (ultimate flower clusters) are pale greenish or yellowish brown and usually are comprised of 4 or 5 flowers. The glumes (small pair of bracts at the base of each spikelet) are about 3 mm (0.1 in) long. The lemma (outer bract at the base of a floret) is 3 to 4 mm (0.1 to 0.2 in) long and has cobwebby hairs at its base. The palea (inner bract at the base of a floret) is 3 to 3.5 mm (about 0.1 in) long and has a sharp, longitudinal ridge. The reddish-brown grain-like fruit is elliptical to spindle-shaped and about 1.5 mm (0.06 in) long.