Longflower Evening Primrose

Erect annual herb, not forming a rosette, unbranched or ± well branched throughout, 4-15 dm tall. Entire plant covered with soft hairs, densely to sparsely long-villous, the hairs erect, densely short villous, and densely glandular pubescent. Cauline leaves narrowly lanceolate, sessile, 5-15 x 0.5-1.5 cm; bracts narrowly lanceolate, sessile, longer than the capsules they subtend, (3-)4-9 x 0.5-1.2 cm; leaves plane or weakly to evidently undulate at the margins, sparsely serrate with blunt teeth. Inflorescence branched. Floral tube 8-11(-13) cm long. Sepals 2-3.5 cm long; sepal tips erect or divergent, 1.5-4 mm long. Petals yellow, broadly obovate, (1.5-)2-4 cm long. Style 9-13.5 cm long; the stigma held above the anthers at anthesis or surrounded by them. Capsules (2-)2.5-4(-5) x 0.3-0.4 cm, thicker in the upper third, 1.5-2 x 0.5-0.6 mm. Self-compatible; outcrossing or self-pollinating. Gametic chromosome number, n = 7 (7 bivalents, ring of 14 or intermediate configurations at meiotic metaphase I).

Distribution: Native in South America from Bolivia and Brazil south to central Argentina and Valparaiso, Chile. Widely naturalized in Europe, Australia, Africa, Asia, and the Hawaiian Island. Not common in Pakistan. Fl. Per.: probably June-August.

O. chilensis Fischer & Meyer, Ind. Sem. Hort. Bot. Petrop. 45. 1835.