Oenothera arida

Herbs perennial, clumped, strigillose and glandular puberulent throughout, also sparsely villous; from stout roots. Stems erect, usually branched several cm belowground or from near base, sometimes also branched distally, 20–60(–100) cm. Leaves in a basal rosette and cauline, basal 2–4 × 0.4–0.8 cm, petiole0–0.4 cm, blade narrowly oblanceolate to narrowly spatulate; cauline 0.5–5 × 0.1–0.8 cm, petiole 0–0.3 cm, blade narrowly lanceolate or very narrowly elliptic, margins subentire or sinuate-denticulate. Flowers 4-merous, nearly actinomorphic, opening near sunset; floral tube 9–13 mm; sepals 7–9 mm; petals white, fading pink to pale red, slightly unequal, rhombic, 7–8 mm, short-clawed; filaments 3–4 mm, anthers 4–5 mm, pollen 85–100% fertile; style 18–22 mm, stigma exserted beyond anthers at anthesis. Capsules erect, fusiform, often slightly curved, weakly 4-angled, (9–)13–17 × 2–3 mm, valves with inconspicuous raised midrib; sessile. Seeds (1–)3 or 4, yellowish or light brown, 2–3.5 × 1–2 mm. 2n = 14.

Phenology: Flowering Apr–Aug.
Habitat: Sandy flats and washes.
Elevation: 1300–1800 m.

Tex., Mexico (Chihuahua).

Discussion

Oenothera arida is known only from several areas in the foothills of the Davis Mountains in eastern Jeff Davis County, northeastern Presidio County, and northern Brewster County, and from areas near Gallego and Chihuahua in Chihuahua, Mexico. P. H. Raven and D. P. Gregory (1972[1973]) determined O. arida to be self-incompatible.

Selected References

None.

Lower Taxa