Annual or short-lived perennial herb to c. 70 cm high; stems erect to procumbent, simple or branched, with spreading and appressed hairs. Basal leaves rosetted, narrow-oblanceolate, 4–15 cm long, 1–3 cm wide, petiolate; cauline leaves oblanceolate to lanceolate or narrowly elliptic, 2–5(–10) cm long, 5–15(–35) mm wide, margins entire to deeply lobed or dentate, acute. Flowers single, sessile in upper leaf axils, actinomorphic, opening near sunset and fading by morning; hypanthium 1.2–3.5 cm long; sepals linear-lanceolate, 5–15 mm long; petals 5–22 mm long, pale yellow to yellow, turning reddish. Capsule ± cylindric, 2–5 cm long, 2–4 mm wide, somewhat curved, with dense spreading and short appressed hair, dehiscing mainly at apex. Flowers Oct.–Jun.
GipP. Also naturalised WA, Qld, NSW. Native to the USA. Known in Victoria from a single population growing near Port Melbourne. .
