8d. Oenothera hartwegii subsp. fendleri (A. Gray) W. L. Wagner & Hoch, Syst. Bot. Monogr. 83: 212. 2007.
Oenothera fendleri A. Gray, Mem. Amer. Acad. Arts, n. s. 4: 45. 1849; Calylophus hartwegii (Bentham) P. H. Raven subsp. fendleri (A. Gray) Towner &P. H. Raven; Galpinsia fendleri (A. Gray) A. Heller; G. hartwegii (Bentham) Britton var. fendleri (A. Gray) Small; O. hartwegii var. fendleri (A. Gray) A. Gray
Herbs usually glabrous throughout, sometimes glandular puberulent on distal parts, especially on ovaries. Leaves 1–5 × 0.15–1 cm, fascicles of small leaves to 1 cm (when present); blade linear to oblanceolate or lanceolate, base attenuate to obtuse, rarely nearly clasping, margins entire or subentire, rarely undulate. Flowers: buds with free tips 0.5–3 mm; floral tube 30–50 mm; sepals 9–28 mm; petals 10–30 mm; filaments 5–12 mm, anthers 5–13 mm; style 40–75 mm. 2n = 14.
Flowering Apr–Oct. In scattered populations on clay or gravelly soil, sometimes calcareous, in grasslands, often with Juniperus and Prosopis, to woodlands with Juniperus, Pinus edulis, sometimes Pinus ponderosa; 300–2200 m; Ariz., Kans., N.Mex., Okla., Tex.; Mexico (Chihuahua).
Subspecies fendleri is known from Barber, Comanche, and Morton counties, Kansas, south through western Oklahoma and scattered sites in the Texas Panhandle to eastern Chihuahua, central trans-Pecos Texas, central and western New Mexico, and east-central Arizona. It is the most distinctive subspecies in the complex.
