Boykinia occidentalis
Brook foam
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Family: Saxifragaceae · Type: Herb · Native
Boykinia occidentalis (Brook foam) is a native California herb in the Saxifragaceae family, recognized by . Intermediate characteristics distinguish it from both others.
Brook foam is a California native perennial found in northwestern California, the northern Sierra Nevada, central coastal California, San Francisco Bay Area, northern southern Coast Ranges, and western Transverse Ranges including Santa Monica Mountains in shady wet banks at elevations below 1,500 meters. Flowering from May to August, this plant produces white flowers in delicate, occasionally coiled inflorescences with petals 3 to 4 millimeters long. Growing 15 to 60 centimeters tall with erect stems, it has a distinctive branching structure with inflorescences that taper to their tips. Its leaves are 6 to 45 centimeters long, divided one-quarter to one-third of the way to the base, with round-sided lobes and teeth, and green stipules occasionally tipped with brown bristles. The plant forms compact clusters along wet, shaded banks with delicate white flower clusters and intricately structured foliage.
Identification and appearance
Key characters: 2 sympatric species. Intermediate characteristics distinguish it from both others.
Habitat and range
Habitat: Shady wet banks
Elevation: < 1500 m
California counties: Humboldt, Sierra, Mendocino, Monterey, Yuba, Santa Cruz, Trinity, Plumas, Siskiyou, San Luis Obispo, Sonoma, Lake, Del Norte, Placer, Butte, Nevada, El Dorado, San Mateo, Marin, Santa Clara, Santa Barbara, Ventura, Amador, Colusa, Solano, Los Angeles, Calaveras, Napa, San Francisco, Glenn, Tehama
Outside California: to British Columbia
Bloom period
Boykinia occidentalis blooms May-Aug.
How to tell it apart
vs Heuchera: Boykinia has large leaves over 4 cm and flat-topped clusters; Heuchera has smaller leaves and branched pyramids; vs Glechoma: Boykinia has flat-topped flower clusters; Glechoma has small paired flowers in leaf axils along square stems; vs Saxifraga: Boykinia has large rounded leaves over 4 cm; Saxifraga has small narrow leaves under 2 cm; vs Tiarella: Boykinia has flat-topped flower clusters; Tiarella has bottlebrush-like spikes; vs Micranthes: Boykinia leaves are over 4 cm with open lobes; Micranthes leaves are under 4 cm with rounded teeth
Frequently asked questions
Is Boykinia occidentalis native to California?
Yes. Boykinia occidentalis is native to California (recorded as native).
When does Boykinia occidentalis bloom?
Boykinia occidentalis blooms May-Aug.
Where in California does Boykinia occidentalis grow?
Boykinia occidentalis occurs in Humboldt, Sierra, Mendocino, Monterey, Yuba, Santa Cruz, Trinity, Plumas and other counties, at elevations of < 1500 m.
What plant family does Boykinia occidentalis belong to?
Boykinia occidentalis is in the Saxifragaceae family, genus Boykinia.
What habitat does Boykinia occidentalis grow in?
Boykinia occidentalis grows in Shady wet banks.
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.