41. Oenothera cinerea (Wooton & Standley) W. L. Wagner & Hoch, Syst. Bot. Monogr. 83: 211. 2007.
[E]
Gaura cinerea Wooton & Standley, Contr. U.S. Natl. Herb. 16: 152. 1913
Herbs suffrutescent, densely soft-villous, hairs mostly appressed, 2–3 mm, becoming less villous distally, also strigillose, rarely glandular puberulent or hispidulous, plant parts grayish green; from deep, twisted, woody rootstock. Stems erect, several-branched near ground, also branched proximal to inflorescences, 60–280 cm. Leaves in a basal rosette and cauline, 0.5–8 × 0.15–2 cm, sessile, blade narrowly lanceolate or oblanceolate to very narrowly elliptic or linear, margins usually subentire or shallowly sinuate-dentate, sometimes deeply sinuate-dentate, often undulate. Inflorescences slender. Flowers 4-merous, zygomorphic, opening near sunset; floral tube 1.5–5 mm; sepals 6–14 mm; petals white, fading pink to red, slightly unequal, elliptic, 7–13 mm, clawed; stamens presented in lower 1/2 of flower, filaments 4.5–11 mm, anthers 2–4.5 mm, pollen 90–100% fertile; style 9–19 mm, stigma exserted beyond anthers at anthesis. Capsules lanceoloid to narrowly ovoid, 4-winged, 9–19 × 1–3.5 mm, abruptly constricted to a long, sterile stipe 2–10 mm. Seeds (1 or)2–4, 2–3(–4) × 0.8–1.3 mm, yellowish to light brown or rarely reddish brown.
Subspecies 2 (2 in the flora): sc United States.
P. H. Raven and D. P. Gregory (1972[1973]) determined Oenothera cinerea to be self-incompatible. The two subspecies recognized here have disjunct distributions but are very similar morphologically.
