Trifolium resupinatum
Reversed clover
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Family: Fabaceae · Type: Herb · Not Native
Trifolium resupinatum (Reversed clover) is a non-native California herb in the Fabaceae family, recognized by . Key features: star-shaped reflexed heads, inflated upper calyx.
Reversed clover is a naturalized annual found in the northern and central Coast Ranges in disturbed areas at elevations below 350 meters. Flowering from April to July, this plant produces distinctive pink to purple flowers in star-shaped heads 1 to 1.5 centimeters wide. Growing with ascending to erect stems, it features delicate diamond-shaped to ovate leaflets 1 to 2.5 centimeters long. Its leaves have ovate to oblong stipules with linear tips, creating an intricate architectural structure. The flower's banner is uniquely notched at the tip, with a calyx that becomes inflated in fruit.
Identification and appearance
Key characters: 33 sympatric species. Key features: star-shaped reflexed heads, inflated upper calyx
Habitat and range
Habitat: Disturbed areas
Elevation: < 350 m
California counties: Marin, Los Angeles, Monterey, Yolo, San Luis Obispo, San Mateo, Napa, Mendocino, Humboldt, Madera, Colusa, Santa Cruz
Outside California: United States, native to Europe, Mediterranean
Bloom period
Trifolium resupinatum 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 resupinatum native to California?
No. Trifolium resupinatum is not native to California (recorded as not native).
When does Trifolium resupinatum bloom?
Trifolium resupinatum blooms Apr-Jul.
Where in California does Trifolium resupinatum grow?
Trifolium resupinatum occurs in Marin, Los Angeles, Monterey, Yolo, San Luis Obispo, San Mateo, Napa, Mendocino and other counties, at elevations of < 350 m.
What plant family does Trifolium resupinatum belong to?
Trifolium resupinatum is in the Fabaceae family, genus Trifolium.
What habitat does Trifolium resupinatum grow in?
Trifolium resupinatum grows in 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.