Ludwigia decurrens - Winged Willow Primrose

Winged Willow Primrose is an annual, erect herb, growing up to 6 ft tall, becoming hairless, with stems 4-winged. Leaves are nearly stalkless, lanceshaped to narrowly elliptic, 3.8-11.5 x 1-2 cm, narrowly wedge-shaped at base, entire at margin, pointed or somewhat tapering at tip, membranous, leaf-stalks about 2.6 mm long. Flowers are about 1.75 cm across, showy, 4-merous; flower-stalks four-edged, 0.6-1.1 mm long. Sepals are 4, ovate-lanceshaped or ovate-tapering, 6-9 x 0.25-0.32 cm, minutely crenulate and purple at margin, hairless or glabrate, 5-nerved. Petals are obovate-elliptic, 0.90-1.22 x 0.4-0.7 cm, abruptly pointed at tip, yellow, 1-nerved. Stamens are 8 (4 + 4), petaliferous ones slightly shorter; filaments about 2.42 mm long, white; anthers about 1 mm long. Ovary is about 7 mm long, 4-angled, with angles winged, 4-celled. Style is thick, about 2 mm long, stigma spherical, about 1.5 mm. Capsules are 1-1.7 x 0.3-0.4 cm, sharply 4-angled or narrowly winged, wings crenulate, greenish to purplish brown. Winged Willow Primrose is native to the American continents, naturalized in Assam and West Bengal, Africa, Japan, China. Flowering: July-November.