Distribution: Occurring east of the Cascades crest, where endemic to the Columbia River region of central Washington.
Habitat: Basaltic cliffs.
Flowers: June-August
Origin: Native
Growth Duration: Perennial
Conservation Status: Endangered in Washington (WANHP)
Pollination: Bees
Prostrate, matted sub-shrub.
Leaves oblanceolate-spatulate, 15-25 mm. long and 2-4 mm. broad, 3-nerved, sparsely appressed-pubescent.
Inflorescence a tight, spikelike, bracteate raceme 2-6 cm. long on a peduncle 5-15 cm. tall, with scattered, bract-like leaves below and more numerous linear, acute bracts above bearing rudimentary buds; pedicles 0.5-2 mm. long; calyx grayish-sericeous, top-shaped, 1 mm. long, with 5 triangular-lanceolate, erect lobes 1.5 mm. long; petals narrowly oblanceolate with a wedge-shaped base, scarcely exceeding the sepals; stamens 20-25; pistils 5, the styles slender, 2 mm. long.
Follicles nearly 3 mm. long.
Publication: North American Flora 22(3): 253. 1908.
Spiraea cinerascens Piper
PNW Herbaria: Specimen records of Petrophytum cinerascens in the Consortium of Pacific Northwest Herbaria database
WA Flora Checklist: Petrophytum cinerascens checklist entry
OregonFlora: Petrophytum cinerascens information
E-Flora BC: Petrophytum cinerascens atlas page
CalPhotos: Petrophytum cinerascens photos
