Muhlenbergia flexuosa Hitchc.

Caespitose perennials. Culms 15−40 cm tall, slender, 0.3−0.4 mm diameter just below the panicle with 6−8 nodes per culm; internodes 1−6 cm long near base, glabrous, shiny. Leaf sheaths about as long as the internodes below, glabrous; ligules 0.3−0.5 mm long, membranous, apex truncate, lacerate; blades 2−5 cm long, 1−2.2 mm wide, flat, scaberulous, apex acuminate. Panicles 3.5−6.5 (−7) cm long, 0.5−1.5 cm wide, narrow, spiciform, sometimes interrupted below; primary branches 0.5−2.5 cm long, tightly apressed to loosely ascending or spreading, not more than 45° from the culm axis. Spikelets 2.8−4.2 mm long, yellowish to light brown, erect or drooping; glumes 2.8−4 mm long, including mucos or awns, subequal, hyaline to membranous, glabrous, 1-veined, scabrous along the midvein, apex acute, unawned, mucronate or awned, the awns up to 1.3 mm long, straight or loosely flexuous; lemmas 2.8−4.2 mm long, hyaline to membranous, 3-veined, scaberulous, lower 1/3 sparsely hairy, apically awned, the awns 14−30 mm long, flexuous, callus hairy, the hairs up to 0.4 mm long; paleas about as long as the lemmas, 2-veined, glabrous, apex acuminate, often mucronate; anthers 1.3−1.6 mm long, purple. Caryopses 1.4−1.6 mm long fusiform, light brown.

Muhlenbergiaflexuosa endemic to Peru and is known from only a few collections from Huánuco, Pasco and San Martín departments (Hitchcock 1927; Tovar 1993).