Plants annual or perennial; monoecious or dioecious; often stoloniferous. Culms 5-40 cm, sometimes decumbent. Leaves mostly basal; sheaths open; ligules of hairs; blades 0.5-2 mm wide. Inflorescences terminal, racemelike panicles of short branches, usually exceeding the upper leaves, sometimes appearing 1-sided; branches about 0.5 cm, not appressed to the rachises, with 3 spikelets, bases strongly curved, shortly strigose, axes not extending beyond the distal spikelets; disarticulation at the base of the branches. Spikelets pedicellate or sessile, lateral spikelets with shorter pedicels than the central spikelet or sessile; lateral spikelets with 2 florets, lower florets usually staminate or sterile, rarely pistillate, upper florets much reduced, usually sterile; central spikelets pedicellate, with 3 florets, lowest florets bisexual or pistillate (staminate in staminate plants), distal florets staminate or sterile. Glumes 2, very unequal, shorter than the spikelets, unawned; lower glumes shorter than the upper glumes, those of the central spikelets flabellate, glabrous, veinless; upper glumes approximately equal to the adjacent lemmas, 1-veined, acuminate; lemmas thinner than the glumes, pilose, 3-veined, 4-lobed, all 3 veins excurrent, forming awns that equal or exceed the lobes, lobes of the sterile florets usually deeper than those of the other florets; paleas 2-veined, veins often extending as awns. x = 10. Name from the Greek kathestekos, set fast or stationary; the allusion is not clear.

Cathestecum is a genus of six species that extends from the southern United States to Guatemala; two are native to the Flora region. Columbus (1999) advocated including Cathestecum in Bouteloua, but the traditional treatment is adopted here.

1.   Cathestecum brevifolium Swallen

Plants perennial; polygamous or dioecious; cespitose, forming dense, small clumps, stoloniferous, stolons thin, internodes to 10(12) cm, straight or only slightly arching. Culms 5-15 cm, erect or geniculate. Leaves primarily basal; lower sheaths densely villous basally, mostly glabrous or sparsely pilose distally, throats densely ciliate; blades 1-5 cm long, 1-2 mm wide, stiff, flat to involute, abaxial surfaces glabrous, adaxial surfaces scabrous and pilose, margins scabrous. Panicles with 3-10 branches; branches divergent, dimorphic, with staminate or bisexual spikelets, spikelets usually reddish or purple. Staminate branches: all spikelets similar; lower glumes to 1 mm, often reduced to a scale, 0-1-veined; upper glumes 1/2-2/3 as long as the spikelets, narrowly trullate to lanceolate, usually glabrous, veins sometimes sparsely pilose, glumes of the lateral spikelets about 2.5 mm, acute or acuminate, those of the central spikelets about 3 mm, minutely lobed and mucronate; lowest lemmas to 3 mm, sparsely pilose, with short lobes, mucronate between the lobes; distal lemmas to 2.5 mm, similar to the lowest lemmas but with deeper lobes; anthers 0.7-2 mm. Bisexual branches: lateral spikelets poorly developed, lower glumes to 1 mm, upper glumes to 2.5 mm, veins pilose, florets greatly reduced, sometimes just a cluster of awns, sterile (rarely staminate); central spikelets with glumes similar to those of the lateral spikelets; lowest florets pistillate, lemmas about 3 mm, scabrous, lobed, lobes about 1/4 as long as the lemmas, awned from the sinuses, awns slightly exceeding the lobes; distal florets staminate or sterile, about 2.5 mm, deeply lobed, awned from the sinuses, awns exceeding the lobes by 1-3 mm. 2n = 20, 40, 60, and 80.

The range of Cathestecum brevifolium extends from Ragged Top Mountain, Arizona, to El Salvador and Honduras. The Arizonan plants were originally identified as Cathestecum erectum but, like many Mexican populations of C. brevifolium, they have 2n = 60 and are dimorphic, consisting of relatively long-awned pistillate plants and more shortly-awned staminate plants (J.R. Reeder, pers. comm.).

2.   Cathestecum erectum Vasey & Hack.
False Grama

Plants perennial; polygamous; cespitose, forming dense, small clumps, stoloniferous, stolons thin, internodes 15-40 cm, strongly arching. Culms 10-30 cm, erect or geniculate, glabrous. Leaves primarily basal; lower sheaths overlapping, densely villous basally, throats pilose; upper sheaths not overlapping, glabrous; ligules about 0.3 mm; blades 3-12 cm long, 1-1.5 mm wide, involute or flat, glabrous abaxially, scabrous and sparsely pilose adaxially, hairs to 2 mm. Panicles with 5-7 branches; branches about 5 mm, dimorphic, staminate or bisexual, the 2 forms sometimes on different plants, sometimes mixed within a panicle, spikelets of 1 form all staminate, bisexual form with pistillate (sometimes bisexual) central spikelets and well-developed staminate or sterile lateral spikelets, spikelets frequently pale green. Staminate branches: all spikelets similar; lower glumes about 1 mm; upper glumes glabrous or almost so, those of the lateral spikelets about 3 mm, those of the central spikelets about 4 mm; lemmas similar, about 3 mm, glabrous, irregularly lobed, unawned, sometimes mucronate. Bisexual branches: glumes villous; lateral spikelets with staminate or sterile florets; lemmas of lateral spikelets about 3 mm, glabrous or sparsely pubescent, irregularly lobed, awned from the sinuses, awns hispid, equaling or occasionally exceeding the lobes; anthers 1.7-2.3 mm; central spikelets with the lowest floret pistillate, distal florets staminate or sterile; lowest lemmas glabrous or sparsely pubescent, lobed, lobes about 1/3 as long as the lemmas, awned from the sinuses, awns glabrous, subequal to the lobes or the central awns slightly longer; distal florets similar to those of the lateral florets, awns 1-2 mm longer than the lobes. 2n = 20.

Cathestecum erectum grows on dry hills in the Great Bend region of western Texas and in northern Mexico.