9. Oenothera tetraptera Cavanilles, Icon. 3: 40. 1796.
四翅月见草 si chi yue jian cao
Herbs decumbent to ascending, annual or short-lived perennial, clumped to suffrutescent. Stems 15-50 cm tall, simple or branched, strigillose, often also moderately villous. Leaves green, with inconspicuous veins, strigillose, subsessile above, petioles 2-8 mm below; basal blade elliptic to narrowly obovate, 3-10 × 1-3 cm; cauline blade oblanceolate to obovate or elliptic-lanceolate, narrower above, 2-5 × 0.6-2.5 cm, base attenuate, margin weakly serrate to sinuate-pinnatifid, often with a large terminal lobe, apex acute to subobtuse. Inflorescence a lax open simple or branched raceme. Flowers open near sunset; floral tube 1-2.9 cm. Sepals 1.6-3.2 cm, with free tips 0.5-3.5 mm. Petals white, fading to rose-purple, 1.6-3.8 cm. Anthers 4-10 mm; pollen ca. 90+% fertile. Ovary densely strigillose and villous; stigma exserted above anthers. Capsule clavate to obovoid, 7.5-18 mm, valves with wings 2-3 mm wide, attenuate to slender sterile stipe (pedicel) 5-37 mm. Seeds clustered in each locule, light brown, obovoid, 1-1.5 mm, papillose. Fl. May-Aug, fr. Jun-Oct. 2n = 14; self-compatible, mostly outcrossing.
Moist disturbed places, mostly along roads and near gardens, where it is sometimes cultivated; 300-2200 m. Guizhou, Sichuan, Taiwan, Yunnan [native to S North America (including Mexico); naturalized in Sri Lanka, SW Asia, Australia, Central America, Europe, and N South America].