Trifolium subterraneum
Subterranean clover, Subterranean Clover
(c) John A Haskins, some rights reserved (CC BY), uploaded by John A Haskins · licence
Family: Fabaceae · Type: Herb · Not Native
Trifolium subterraneum (Subterranean clover) is a non-native California herb in the Fabaceae family, recognized by . Key features: peduncle grows into ground, bur-like fruit.
Subterranean clover is a naturalized annual found in northern Sierra Nevada, Central Valley, northern and southern Coast Ranges, and other regions in meadows, roadsides, and disturbed areas at elevations below 1,000 meters. Flowering from March to April, this plant produces predominantly white flowers in compact heads about one centimeter wide. Growing with prostrate or creeping hairy stems that root along the ground, it spreads in low, sprawling patches. Its leaves have three leaflets 10 to 15 millimeters long, each obovate or heart-shaped, with wide stipules that taper to a point. In a unique adaptation, the plant's flower stalks curve and grow into the ground after flowering, delivering its fruits directly into the soil.
Identification and appearance
Key characters: 58 sympatric species. Key features: peduncle grows into ground, bur-like fruit
Habitat and range
Habitat: Meadows, roadsides, disturbed areas
Elevation: < 1000 m
California counties: Humboldt, Santa Cruz, Mendocino, Marin, Napa, Merced, Sonoma, San Luis Obispo, El Dorado, Nevada, Calaveras, Placer, San Francisco, Sacramento, Tehama, Alameda, Solano, Contra Costa, Butte, Yuba, Glenn, Stanislaus, Del Norte, San Mateo, San Diego, Santa Clara, Yolo, Colusa, Shasta, Sutter, Lake, Monterey
Outside California: sporadic United States, native to southern Europe, northern Africa
Bloom period
Trifolium subterraneum blooms Mar-Apr.
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 subterraneum native to California?
No. Trifolium subterraneum is not native to California (recorded as not native).
When does Trifolium subterraneum bloom?
Trifolium subterraneum blooms Mar-Apr.
Where in California does Trifolium subterraneum grow?
Trifolium subterraneum occurs in Humboldt, Santa Cruz, Mendocino, Marin, Napa, Merced, Sonoma, San Luis Obispo and other counties, at elevations of < 1000 m.
What plant family does Trifolium subterraneum belong to?
Trifolium subterraneum is in the Fabaceae family, genus Trifolium.
What habitat does Trifolium subterraneum grow in?
Trifolium subterraneum grows in Meadows, roadsides, disturbed areas.
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.