Oenothera sect. Eremia

Herbs winter-annual, caulescent to short-caulescent; from a weakly fleshy taproot. Stems (when present) ascending to erect, branched or unbranched. Leaves in a basal rosette, sometimes also cauline, (1.4–)6–15(–28) cm; blade margins sinuate-dentate to subentire. Inflorescences solitary flowers in axils of leaves. Flowers opening near sunset, with strong, sweet, lemony scent or pungent, spermaceous scent, to weakly scented in autogamous populations; bud apex curved downward by recurved floral tube, becoming erect before anthesis, quadrangular, without free tips; floral tube (20–)26–60(–72) mm; sepals separating individually or in pairs; petals deep yellow, fading reddish orange to purple, drying purple, obcordate to obovate; stigma deeply divided into 4 linear lobes. Capsules hard, woody in age, sigmoid or curved to nearly straight, lanceoloid to ovoid, 4-angled, apex gradually tapering to a sterile beak, dehiscent 1/4–2/3 their length; sessile. Seeds usually numerous, in 2 rows per locule, obovoid to oblanceoloid, surface papillose, coarsely rugose on distal 1/2 abaxially, adaxial face thickened with a cavity that externally appears as a pore and groove along raphae. 2n = 14.

Distribution

sw United States, n Mexico.

Discussion

Species 1.

Section Eremia consists of a single species that occurs in the Chihuahuan, Mojave, and Sonoran deserts.

Selected References

None.

Lower Taxa

Oenothera primiveris