5b. Oenothera capillifolia subsp. berlandieri (Spach) W. L. Wagner & Hoch, PhytoKeys. 28: 71. 2013.
Calylophus berlandieri Spach, Ann. Sci. Nat., Bot., sér. 2, 4: 273. 1835 (as Calylophis); C. drummondianus Spach subsp. berlandieri (Spach) Towner & P. H. Raven; Meriolix berlandieri (Spach) Walpers
Herbs perennial. Stems several–many, decumbent to ascending, moderately branched, (10–)25–40 cm. Leaves 1–4 × (0.1–)0.3–0.6 cm; blade margins subentire or serrate, sometimes weakly undulate. Flowers: buds with free tips 0–2 mm; sepals often with slightly keeled midribs. 2n = 14.
Flowering Mar–Sep. Grassy prairies, plains, low hills, sandy, gravelly, and limestone soil, relatively dry areas, in vegetation dominated by mesquite, oaks, and Opuntia; 0–1200 m; Kans., N.Mex., Okla., Tex.; Mexico (Coahuila, Nuevo León).
Subspecies berlandieri occurs in Meade, Reno, and Seward counties in Kansas, south through eastern New Mexico, the Texas Panhandle, and western Oklahoma to Crane, Culberson, and Ward counties in Texas, southeastward to near the Pecos and Rio Grande rivers to the Gulf Coast, becoming widespread on the Coastal Plain north to Milam County in Texas; it also occurs in the Santa Rosa Mountains of northern Coahuila, Mexico.