(Oenothera heterophylla heterophylla)
Oenothera rhombipetala is described by Dietrich and Wagner (1988) as an erect biennial 30-100 cm (1.0-3.3 ft.) tall, sometimes with lateral branches arising from the base. The stem is densely to sparsely covered with short, stiff hairs and sometimes glandular hairs in the upper parts. The basal leaves are 6-20 cm (2.4-7.9 in.) long and 0.6-2 cm (0.2-0.8 in.) wide, narrowly oblanceolate in shape with toothed or lobed margins, an acutely pointed tip, and a gradually narrowed base.