Plants perennial; cespitose. Culms 10-60 cm, erect to somewhat decumbent, usually branched. Sheaths open, compressed-keeled, glabrous, smooth or scabridulous, mostly shorter than the internodes, a 2-veined prophyllum often present; ligules hyaline, strongly decurrent, truncate or rounded to elongate and acuminate, sometimes with narrow triangular lobes extending from the edges of the sheath on either side; blades folded or flat, rather stiff, with prominent, firm, scabrous margins, midveins sometimes extending as short mucros or fragile, scabrous, awnlike apices. Inflorescences terminal and axillary, dense, bristly, spikelike panicles; branches short, fused to the rachis, terminating in a pair of unequally pedicellate spikelets or a pedicellate spikelet and a short secondary branch with two spikelets, occasionally in a solitary spikelet, usually the lower spikelet in a pair staminate or sterile and the upper spikelet bisexual, sometimes vice versa, or both spikelets bisexual; disarticulation at the fused base of the pedicels or pedicel and branch, paired spikelets falling as a unit, leaving a cuplike tip. Spikelets with 1 floret. Glumes subequal, awned; lower glumes with (1)2(3) awns, usually unequal, awns commonly longer than the body; upper glumes 1-veined, with a single flexuous awn that is usually longer than the glume body, rarely a finer second awn present; lemmas lanceolate, 3-veined, pubescent on the margins, mostly glabrous over the back, tapering to a scabrous awn that is usually shorter than the lemma body; paleas about equal to the lemmas, acute or occasionally the 2 veins extending as very short mucros, pubescent between the veins and on the sides, except for the narrow, glabrous, hyaline margins; anthers 3. Caryopses fusiform, brownish. x = 10. Name from the Greek lykos, wolf, and oura, tail, an allusion to the spikelike inflorescences.

Lycurus is a genus of three species that grow on open rocky slopes and mesas. It is native to two disjunct regions, one extending from Colorado and southern Utah to southern Mexico and Guatemala, the other from Colombia through western South America to west-central Argentina. Two species are native to the Flora region. They can only be reliably distinguished by their vegetative characters.

1.   Lycurus setosus (Nutt.) C. Reeder
Bristly Wolfstail

Plants densely cespitose. Culms 30-50(60) cm, erect, with several nodes, sparingly branched, scabrous to puberulent at or near the nodes. Ligules (2)3-10(12) mm, hyaline, acuminate, sometimes shortly cleft on the sides (in dried specimens the fragile ligules may appear shorter because of the folded tip); blades 4-9(13) cm long, 1-2 mm wide, glabrous, smooth or scabridulous abaxially, scabridulous or hispidulous adaxially, with prominent whitish midribs and scabrous margins, midribs extending as fragile, easily broken, awnlike, (3)4-7(12) mm apices. Panicles 4-8(10) cm long, (5)7-8 mm wide; shorter pedicels 0.8-1(1.5) mm; longer pedicels 1-2 mm. Spikelets 3-4 mm. Glumes 1-1.5(2) mm, scabrous apically; lower glumes2-veined, with (1)2(3) unequal scabridulous awns, shorter awns 1-1.5 mm, longer awns (1)1.5-3(3.5) mm; upper glumes 1-veined, with a single, flexuous 2.5-4(5) mm awn; lemmas 3-4 mm, tapering to a scabrous 1.5-2(3) mm awn; anthers 1.5-2 mm, yellowish. Caryopses about 2 mm, brownish. 2n = 40.

Lycurus setosus grows on rocky slopes and open mesas, at elevations of 570-3400 m. Its range extends from the southwestern United States to northern Mexico, and, as a disjunct, in Argentina and Bolivia. It was found as an adventive (associated with wool waste) in North Berwick, York County, Maine, in 1902, but it has not been reported from there since. Its flowering time is July-October.

Lycurus setosus is sometimes confused with Muhlenbergia wrightii, which has a somewhat similar aspect but is normally found in moist habitats. Also, in M. wrightii the first glume is 1-veined with a very short awn, and the lemma is acuminate and unawned or with an awn no more than 1 mm long.

Peterson and Columbus state that this species should be transferred to Muhlenbergia as M. alopecuroides but do not explicitly address the position of the other two species of Lycurus. It is retained in Lycurus until the appropriate treatment of the whole genus has been discussed.

2.   Lycurus phleoides Kunth
Common Wolfstail

Culms 20-50 cm, erect to ascending, often geniculate. Ligules 1.5-3 mm, commonly acute to acuminate, with narrow triangular lobes 1.5-3(4) mm long extending from the sides of the sheaths; blades 4-8 cm long, 1-1.5 mm wide, acute or mucronate, midribs sometimes extending up to 3 mm as a short bristle. Similar to Lycurus setosus in inflorescence and spikelet characters, except the upper glumes occasionally with a second shorter, more delicate awn. 2n = 40, ca. 40.

Lycurus phleoides grows on rocky hills and open slopes, at elevations of 670-2600 m. It grows from the southwestern United States to southern Mexico, and in northern South America. It flowers from July-October.