Oenothera greggii A. Gray var. pubescens A. Gray, Smithsonian Contr. Knowl. 3(5): 72. 1852; Calylophus hartwegii (Bentham) P. H. Raven subsp. pubescens (A. Gray) Towner & P. H. Raven; C. hartwegii var. pubescens (A. Gray) Shinners; Galpinsia camporum Wooton & Standley; G. greggii (A. Gray) Small; G. interior Small; G. lampasana (Buckley) Wooton & Standley; O. camporum (Wooton & Standley) Tidestrom; O. greggii A. Gray; O. greggii var. lampasana (Buckley) Munz; O. interior (Small) G. W. Stevens; O. lampasana Buckley

Herbs densely pubescent with mixture of hair types, always short-pilose, especially on ovary and stem, usu­ally also hirtellous, especially on stem and distal parts, sometimes also strigillose, especially on leaves, or glan­dular puberulent distally. Leaves 0.6–4 × 0.15–1.2 cm, fascicles of small leaves often absent or much reduced, sometimes to 1.5 cm; blade very narrowly elliptic or narrowly lanceolate to ovate, base truncate or subcordate and clasping, rarely nearly clasping, margins entire or sparsely serrulate, rarely crinkled-undulate. Flowers: buds with free tips 0.5–3 mm; floral tube 20–50 mm; sepals 9–26 mm; petals 12–35 mm; filaments 5–12 mm, anthers 4–13 mm; style 25–70 mm. 2n = 14, 28.

Flowering Mar–Oct. Colonial in moderately dry, open places, plains, hills, sandy to gravelly soil, limestone or gypsum, grasslands with Juniperus and Prosopis; 200–2100 m; Ariz., Colo., Kans., N.Mex., Okla., Tex.; Mexico (Coahuila, Durango).

Subspecies pubescens occurs from Baca and Las Animas counties, Colorado, Clark, Meade, Morton, and Seward counties, Kansas, to western Oklahoma and the Texas Panhandle, throughout central and trans-Pecos Texas, west through eastern and southern New Mexico to central and southeastern Arizona, and also very locally in northern Mexico.