Hydrophyllum occidentale
Western waterleaf, Western Waterleaf
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Family: Hydrophyllaceae · Type: Herb · Native
Hydrophyllum occidentale (Western waterleaf) is a native California herb in the Hydrophyllaceae family, recognized by . Key features: dense spherical inflorescence, broad calyx lobes.
Western waterleaf is a California native perennial found in northwestern California, the Cascade Range, Sierra Nevada, Sacramento Valley, and San Francisco Bay Area in moist, shaded slopes, woodlands, meadows, streambanks, and chaparral, including serpentine soils at elevations of 375 to 3,000 meters. Flowering from April to July, this plant produces white to lavender flowers with delicate bell-shaped corollas 7 to 11 millimeters long. Growing 10 to 60 centimeters tall with erect stems in flower and a short to long rhizome, it has a distinctive appearance with overlapping petiole bases. Its leaves are complex, with large basal leaves 10 to 30 centimeters long featuring 7 to 15 lobed leaflets that are oblong in shape and sparsely hairy. The plant produces small fruits approximately 4 millimeters in diameter, containing one to two light or dark brown seeds.
Identification and appearance
Key characters: 3 sympatric species. Key features: dense spherical inflorescence, broad calyx lobes
Habitat and range
Habitat: Moist, shaded slopes, woodland, meadows, streambanks, chaparral, including serpentine soils
Elevation: (70)375-3000 m
California counties: Fresno, Tulare, Kern, Tuolumne, Plumas, Sierra, Trinity, Tehama, Shasta, Siskiyou, Lake, Mendocino, Mariposa, Napa, Alameda, Lassen, Mono, Alpine, Nevada, Santa Clara, El Dorado, Humboldt, Placer, Butte, Glenn, Contra Costa, Colusa, Calaveras, Madera, Del Norte, Inyo, San Benito
Outside California: to Washington, Idaho, Utah, Arizona
Bloom period
Hydrophyllum occidentale blooms Apr-Jul.
How to tell it apart
vs Phacelia: Hydrophyllum is a large perennial with stamens extending beyond petals; Phacelia is typically annual with included stamens.; vs Petasites: Hydrophyllum has leaves lobed to the midrib; Petasites has very large unlobed heart-shaped or kidney-shaped leaves.; vs Eucrypta: Hydrophyllum is a robust perennial; Eucrypta is a delicate sticky annual with much smaller flowers.; vs Emmenanthe: Hydrophyllum has stamens extending beyond spreading flowers; Emmenanthe has drooping bell flowers with included stamens.; vs Nama: Hydrophyllum is a large woodland perennial; Nama is a low mat-forming plant of dry sandy areas.
Frequently asked questions
Is Hydrophyllum occidentale native to California?
Yes. Hydrophyllum occidentale is native to California (recorded as native).
When does Hydrophyllum occidentale bloom?
Hydrophyllum occidentale blooms Apr-Jul.
Where in California does Hydrophyllum occidentale grow?
Hydrophyllum occidentale occurs in Fresno, Tulare, Kern, Tuolumne, Plumas, Sierra, Trinity, Tehama and other counties, at elevations of (70)375-3000 m.
What plant family does Hydrophyllum occidentale belong to?
Hydrophyllum occidentale is in the Hydrophyllaceae family, genus Hydrophyllum.
What habitat does Hydrophyllum occidentale grow in?
Hydrophyllum occidentale grows in Moist, shaded slopes, woodland, meadows, streambanks, chaparral, including serpentine soils.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · Index of California Plant Names · CalPhotos
Last updated 2026-10-07
Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Cal-IPC, and more.