Taxon 19: 341. 1970.
Plants, 3-5 dm. Leaves: petiole 1-3 cm. Central leaflet blade ca. 7-16 × 8-17 cm, proximal margins entire, distal margins (3-)6-9(-12)-lobed. Inflorescences 2.8-5.8 cm excluding peduncle. Flowers: stamens 3.8-6 mm; ovaries 1.5-2 mm. Follicles brown, 3.5-5 mm. 2n = 24.
Phenology: Flowering spring–summer (Apr–Jul).
Habitat: Coastal and mountainous regions, Sequoia sempervirens and Pseudotsuga menziesii forests
Elevation: 0-1200 m
B.C., Calif., Oreg., Wash.
Triploid plants have been reported from one locality in central Washington and from a site in northwestern California.