Oenothera guadalupensis S. Watson subsp. clementina P. H. Raven, Aliso 5: 332. 1963; Camissonia guadalupensis (S. Watson) P. H. Raven subsp. clementina (P. H. Raven) P. H. Raven

Herbs annual, subsucculent and heavy-set, densely villous, also glandular puberulent distally. Stems erect, with branches usually arising near base, 2–18(–35) cm. Leaves 1.2–3.8(–9.5) × 0.5–1.2(–1.8) cm; petiole 0–3 cm; blade (basal and proximal cauline) narrowly elliptic, (cauline) narrowly ovate, base attenuate, margins sparsely and inconspicuously denticulate, apex (basal) acute, (cauline) obtuse, rounded, or truncate. Flowers opening near sunrise; floral tube 1.6–2.4 mm; sepals 1.9–3.2 mm; petals yellow, each with 1 red dot near base, 2.8–4.2 mm; episepalous filaments 1.3–2.3 mm, epipetalous filaments 0.4–1.6 mm, anthers 0.4–0.8 mm, less than 5% of pollen grains 4- or 5-pored; style 3.2–4.5 mm, stigma surrounded by anthers at anthesis. Capsules stout, straight or slightly curved outward, 4-angled, 10–18 × 2.8–3.5 mm, deeply grooved along lines of dehiscence. Seeds 0.7–0.9 mm. 2n = 14.

Flowering Mar–Jun(–Sep). Sandy flats, dunes; 0–60 m; Calif.

Subspecies clementiana is restricted to San Clemente Island, Los Angeles County, where it is common on dunes around the north end and down the west shore, perhaps to the south end.