Onagra jamesii (Torrey & A. Gray) Small; Oenothera communis H. Léveillé var. jamesii (Torrey & A. Gray) H. Léveillé

Herbs biennial or winter-annual, usually predominately and densely strigillose, sometimes also villous with scattered, appressed hairs, rarely with a few pustulate hairs, inflorescence sometimes also glandular puberulent. Stems erect, usually green, rarely flushed with red, unbranched or with branches arising obliquely from rosette and secondary branches arising from main stem, 60–180 cm. Leaves in a basal rosette and cauline, basal 10–30 × 2.5–5 cm, cauline 4–20 × 1–5 cm; blade dull green, flat, narrowly oblanceolate, oblanceolate to narrowly elliptic, or narrowly lance­olate, margins bluntly dentate or subentire, teeth widely spaced; bracts persistent. Inflorescences erect, usually unbranched, rarely with few lateral branches. Flowers opening near sunset; buds erect, 7–12 mm diam., with free tips terminal, erect, 0.5–3 mm; floral tube persist­ent on ovary after anthesis, (60–)80–120(–160) mm; sepals yellowish green, red-striped to red throughout, 30–55 mm; petals yellow, fading orange or pale yellow, very broadly obcordate, 40–50 mm; filaments 23–30 mm, anthers 12–22 mm, pollen 90–100% fertile; style 90–170(–200) mm, stigma exserted beyond anthers at anthesis. Capsules erect or slightly spreading, dull green or gray-green when dry, narrowly lanceoloid, 20–50 × 6–12 mm, free tips of valves 2.5–5 mm. Seeds 1–1.2 × 0.7–1.3 mm. 2n = 14.

Flowering Jul–Sep(–Oct). Sandy stream banks, ditches, moist areas, cultivated areas, disturbed roadsides; (30–)300–1800 m; Kans., Okla., Tex.; Mexico (Coahuila, Nuevo León, Puebla); introduced in e Asia (Japan), s Africa, Atlantic Islands (Canary Islands).

Oenothera jamesii has plastome I and a AA genome composition; it is known in the flora area from southern Kansas (Clark County), central Oklahoma, and Texas.