Oenothera cespitosa subsp. cespitosa

Herbs acaulescent or short-caulescent, glabrous or densely strigillose or hairs sometimes ± spreading, rarely sparsely glandular puberulent on flower parts. Stems (if present) usually unbranched, rarely with 1–several short laterals, 0–6(–21) cm. Leaves (2.8–)7–16(–21) × (0.3–)1–3(–5) cm; petiole (1–)3–7(–10) cm; blade obovate to linear-oblanceolate, margins coarsely and irregularly serrate or dentate, sometimes pinnately lobed or subentire. Flowers: floral tube (20–)40–60(–85) mm; sepals (15–)24–35(–40) mm; petals fading rose pink to dark rose purple, (16–)25–40(–48) mm; filaments (12–)15–24(–26) mm, anthers 9–12 mm; style (45–)60–120 mm. Capsules falcate or sigmoid, becoming nearly straight at maturity, asymmetrical and often somewhat flattened, lanceoloid to ovoid, (10–)20–40(–50) × 4–6 mm, valve margins with prominent, sinuate ridge with 5–10 peaks, or nearly distinct tuber­cles; pedicel 0.5–3 mm. Seeds narrowly obovoid, 2.5–3.9 × 1.2–1.7 mm embryo 1/2–2/3 of seed volume, surface papillose; seed collar oblong, membrane depressed deeply into raphial cavity, margin usually sinuate only distally, sometimes sinuate throughout. 2n = 14.

Phenology: Flowering May–Jul(–Aug).
Habitat: Scattered or forming colonies in open sites, loose to hard, compacted clay, sandy soil, rocky slopes of shale, volcanic, or fine sandstone, gumbo flats, badlands, bluffs, exposed rocky ridges, roadcuts, grasslands, sagebrush, shadscale scrub, exposed sites in montane conifer forests.
Elevation: 800–3100 m.

Distribution

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Alta., Man., Sask., Colo., Idaho, Mont., Nebr., Nev., N.Dak., Oreg., S.Dak., Utah, Wash., Wyo.

Discussion

Selected References

None.

Lower Taxa

None.