Herbs perennial, acaulescent; from a thick, fleshy taproot. Leaves in a basal rosette, 2.6–4 (–6.2) cm; blade margins pinnately lobed, lateral lobes often greatly reduced. Inflorescences solitary flowers in axils of leaves. Flowers opening near sunset, with strong, sweet scent; buds erect, quadrangular, without free tips; floral-tube 27–45 (–55) mm; sepals separating individually or in pairs; petals intensely yellow, fading deep salmon red, obcordate; stigma deeply divided into 4 linear lobes. Capsules moderately thin and flexible, lanceoloid, often contorted and twisted, 4-angled, gradually tapering to a long, slender, sterile apex, dehiscent 2/3–3/4 their length; sessile. Seeds numerous, in 1 row per locule, often forming 2 rows near base of capsule, obovoid, surface coarsely rugose, with turgid and collapsed papillae. 2n = 14.

Distribution

w United States

Discussion

Species 1.

Selected References

None.

Lower Taxa

Oenothera xylocarpa

"/3" is not declared as a valid unit of measurement for this property."thin" is not a number.