Distribution: Occuring sporadically throughout central and eastern Washington; widespread throughout much of western U.S. and central Canada.
Habitat: Talus slopes, road cuts, and dry hills.
Flowers: May-July
Origin: Native
Growth Duration: Perennial
Conservation Status: Sensitive in Washington (WANHP)
Pollination: Bees, moths
Tufted, acaulescent to short-stemmed perennial, under 2.5 dm. tall, glabrous to densely pubescent.
Leaves basal, narrowly to broadly oblanceolate, 10-25 cm. long and 1-2.5 cm. broad, with slender petioles about equal to the blades; blades pinnatifid to remotely toothed or nearly entire.
Flowers sessile or with short pedicels; calyx tube greenish or reddish, flared above, 5-12 cm. long, the 4 lobes reflexed, 2.5-3.5 cm. long; petals 4, 2.5-4.5 cm. long, white, aging to pinkish, obcordate; stamens 8, stigma with 4 lobes 5-8 mm. long; ovary inferior, 4-celled.
Capsule woody, oblong-ovoid, 1-4 cm. long, angled but not winged.
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ssp. cespitosa – butte primrose, fragrant evening primrose, rock rose
Sporadic in central and eastern Washington; widespread throughout western U.S. and central Canada. -
ssp. marginata – fragrant evening-primrose Occurring in southeastern Washington; widespread throughout western North America and into Texas.
PNW Herbaria: Specimen records of Oenothera cespitosa in the Consortium of Pacific Northwest Herbaria database
WA Flora Checklist: Oenothera cespitosa checklist entry
OregonFlora: Oenothera cespitosa information
E-Flora BC: Oenothera cespitosa atlas page
CalPhotos: Oenothera cespitosa photos
