Oenothera deltoides subsp. piperi
Aliso 5: 180. 1962.
Herbs annual, usually villous, hairs relatively long, curly, especially distally and on buds, sometimes glabrous; from a taproot. Stems: central stem thickened proximally, unbranched or with several lateral, ascending to decumbent branches, 3–30(–40) cm. Leaves basal and cauline; blade rhombic, becoming lanceolate distally, margins deeply sinuate-dentate to pinnatifid. Flowers: buds fluted or strongly quadrangular in distal 1/2, without free tips; sepals 13–22(–27) mm; petals 15–25(–30) mm. Capsules 15–25(–30) × 3–5 mm. 2n = 14.
Phenology: Flowering (Mar–)Jun–Jul(–Sep).
Habitat: Sandy soil or dunes in Great Basin Desert with Artemisia, Ericameria, or Sarcobatus.
Elevation: 900–1900 m.
Distribution
Calif., Nev., Oreg.
Discussion
W. M. Klein (1964) determined subsp. piperi to be self-incompatible. It occurs in the northern part of the range of O. deltoides, from northeastern California to southern Oregon and the western half of Nevada.
Selected References
None.