Trifolium vesiculosum
Arrowleaf clover
(c) Douglas Goldman, some rights reserved (CC BY-SA), uploaded by Douglas Goldman · licence
Family: Fabaceae · Type: Herb · Not Native
Trifolium vesiculosum (Arrowleaf clover) is a non-native California herb in the Fabaceae family, recognized by . Key features: 24-veined inflating sepals, grooved stems.
Arrowleaf clover is a naturalized annual found in coastal and central California regions including northern Coast Ranges, southern Sacramento Valley, central Coast, and San Francisco Bay Area in disturbed roadsides at elevations below 300 meters. Flowering from July to November, this plant produces pink to purple flowers in dense heads 4 to 6 centimeters long. Growing with erect or ascending stems 15 to 60 centimeters tall that are distinctly grooved, it has a robust and glabrous appearance. Its leaves have three leaflets that are 1.5 to 3 centimeters long, generally lanceolate to elliptic with distinctive bristle-like teeth along the margins. The flower heads are typically positioned above a pair of bract-like leaves, with calyx tubes marked by 24 prominent veins that connect laterally.
Identification and appearance
Key characters: 48 sympatric species. Key features: 24-veined inflating sepals, grooved stems
Habitat and range
Habitat: Disturbed roadsides
Elevation: < 300 m
Outside California: United States, native to Mediterranean
Bloom period
Trifolium vesiculosum blooms Jul-Nov.
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 vesiculosum native to California?
No. Trifolium vesiculosum is not native to California (recorded as not native).
When does Trifolium vesiculosum bloom?
Trifolium vesiculosum blooms Jul-Nov.
What plant family does Trifolium vesiculosum belong to?
Trifolium vesiculosum is in the Fabaceae family, genus Trifolium.
What habitat does Trifolium vesiculosum grow in?
Trifolium vesiculosum grows in Disturbed roadsides.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · 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.