Trifolium obtusiflorum
Clammy clover
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Family: Fabaceae · Type: Herb · Native
Trifolium obtusiflorum (Clammy clover) is a native California herb in the Fabaceae family, recognized by . Key features: sticky glandular hairs, large flowers.
Clammy clover is a California native annual herb found in northwestern and central California, central western California, southern California coastal areas, San Gabriel Mountains, and Peninsular Ranges in moist disturbed areas, gravel bars, and marshes at elevations of 30 to 1,800 meters. Flowering from April to July, this plant produces pale lavender to dull purple flowers with white tips in dense heads 1.5 to 3 centimeters wide. Growing with erect, glandular-hairy stems that are generally sticky and robust, it has a distinctive appearance. Its leaves have 3 leaflets that are narrowly elliptic, 2 to 4 centimeters long, with sharply serrate edges and teeth approximately 1 millimeter long. The flower's calyx is 9 to 11 millimeters long and glandular-hairy, with bristle-tipped lobes that add to its unique texture.
Identification and appearance
Key characters: 54 sympatric species. Key features: sticky glandular hairs, large flowers
Habitat and range
Habitat: Moist disturbed areas, gravel bars, marshes
Elevation: 30-1800 m
California counties: Los Angeles, Tuolumne, San Diego, Riverside, San Bernardino, Fresno, Amador, Glenn, Tehama, Tulare, Mendocino, Madera, Mariposa, San Luis Obispo, Lake, Santa Cruz, Monterey, Stanislaus, Orange, Contra Costa, Napa, Colusa, El Dorado, Del Norte, Sonoma, Humboldt, Trinity, Nevada, Merced, Kings, Butte, Sutter, Plumas, Siskiyou, Alameda, Marin, Santa Clara, Calaveras, Solano, Ventura, Santa Barbara, Yuba, Placer, San Mateo
Outside California: southwestern Oregon
Bloom period
Trifolium obtusiflorum blooms Apr-Jul.
How to tell it apart
vs Medicago: Trifolium flowers persist around fruits; Medicago flowers fall off leaving exposed coiled fruits.; vs Oxalis: Trifolium has pea-shaped flowers; wood-sorrels (Oxalis) have 5-petaled star-shaped flowers and heart-notched leaflets.; vs Melilotus: Trifolium flowers persist enclosing fruits; Melilotus flowers fall off leaving exposed ridged pods.; vs Castilleja: Trifolium has pea flowers and 3 toothed leaflets; paintbrush (Castilleja) has tubular flowers in colorful bracts.; vs Acmispon: Trifolium leaflets have toothed edges; Acmispon leaflets have smooth untoothed margins.
Frequently asked questions
Is Trifolium obtusiflorum native to California?
Yes. Trifolium obtusiflorum is native to California (recorded as native).
When does Trifolium obtusiflorum bloom?
Trifolium obtusiflorum blooms Apr-Jul.
Where in California does Trifolium obtusiflorum grow?
Trifolium obtusiflorum occurs in Los Angeles, Tuolumne, San Diego, Riverside, San Bernardino, Fresno, Amador, Glenn and other counties, at elevations of 30-1800 m.
What plant family does Trifolium obtusiflorum belong to?
Trifolium obtusiflorum is in the Fabaceae family, genus Trifolium.
What habitat does Trifolium obtusiflorum grow in?
Trifolium obtusiflorum grows in Moist disturbed areas, gravel bars, marshes.
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.