Muhlenbergia caxamarcensis Laegaard & Sánchez Vega

Loosely caespitose perennials. Culms 8−12 cm tall, 0.2−0.4 mm diameter just below the panicle, erect to decumbent near base, slender, scaberulous to glabrous, profusely branched below; lower internodes 5−10 mm long with repeated intravaginal branching. Leaf sheaths 4−27 mm long, glabrous, generally longer than the internodes, rounded near base; ligules (1.5−) 1.8−2.5 mm long, hyaline, often lacerate, margins decurrent, apex obtuse; blades 0.5−1.5 cm long, 0.6−1.2 mm wide, flat or folded, prominently veined, sometimes conspicuously crystalline or spiculate on both surfaces, otherwise glabrous below, sparsely scaberulous above and along margins, tapering to a boat shaped tip. Panicles (1.0−)1.5−4.0 cm long, 1−3 mm wide, exserted or included in the uppermost sheath, loosely contracted, narrow; primary branches 0.5−2 cm long, appressed to the culm axis, one per node.pedicels 1−5 mm long, stiff, densely scabrous, spiculate, erect; nodes 4−6 per inflorescence. Spikelets 2.4−2.8 mm long (excluding the mucro or awn), plumbeous to reddish-purple; glumes 1.2−1.6 mm long, shorter than the floret, subequal to equal, 1-nerved, glabrous, often reddish-purple near apex and greenish-grey below, apex obtuse; lemmas 2.4−2.8 mm long, lanceolate, keeled, prominently 3-nerved, dark reddish-purple to plumbeous above greenish-grey below, sericeous, lower ½ to ¾ with scattered appressed hairs, the hairs 0.3−0.5 mm long, apex acuminate, mucronate or short-awned, the awn up to 1.5 mm long, scabrous; paleas 2.4−2.6 mm long, as long as the lemma, lanceolate, hairy between the nerves; anthers 1−1.3 mm long, purple or yellow. Caryopses 0.9−1.1 mm long, elliptic to fusiform, terete, yellowish-brown.

This species is endemic to Peru, known only from Cajamarca and La Libertad departments.