Large, woody, erect to spreading shrub with many stems and branches. Stems red-brown, turning gray with age. Leaves opposite, deciduous, oval to egg-shaped, 1–4 in. long, entire to toothed, with 3 veins running from base to tip of leaf. Flowers fragrant, 6 or more clustered at end of stem, about 1 in. across, with 4 or occasionally 5 white petals, many stamens with large amounts of yellow pollen clustered in center. Grows in moist woods, conifer forests, rocky canyons, at low to mid-elevations throughout western North America. State flower of Idaho. First collected by Lewis and Clark and named for Meriwether Lewis.
- Rarity: Common
- Flowering Time: Early Summer
- Life Cycle: Perennial
- Height: 3--9 feet
- Habitat: East-Side Forest, West-Side Forest
- Found In: Olympic Np, Mt. Rainier Np
- Native: Yes