Canadian River wild buckwheat

Plants 10-20(-25) dm. Aerial flowering stems glabrous or nearly so. Leaves basal and cauline; basal: petiole 2-5, strigose, blade linear-lanceolate to lanceolate, 8-20 × 0.5-1.5 cm, slightly strigose or glabrous adaxially, glabrous abaxially except for strigose margins and midveins; cauline: blade 1-9 cm. Inflorescences 2-6.5 dm; branches glabrous. Peduncles glabrous or occasionally slightly strigose.  Involucres glabrous. Perianths yellow to yellowish green or maroon. Achenes 5.5-9 × 3-5.5 mm. 2n = 40.

Flowering Jul-Oct. Sandy to gravelly flats and gentle slopes, mixed grassland, saltbush, and mesquite communities, oak woodlands; 300-1400 m; N.Mex., Okla., Tex.

Variety glabriusculum is a distinctive taxon of the southern Great Plains, often being the tallest plants on the low, rolling hills. It is geographically isolated from var. alatum, being found near Ruth in Curry County, New Mexico, in western Oklahoma, and in northern Texas.