Euphorbia lathyris
Caper spurge, Caper Spurge
(c) Douglas Goldman, some rights reserved (CC BY-SA), uploaded by Douglas Goldman · licence
Family: Euphorbiaceae · Type: Herb · Not Native
Conservation status: Cal-IPC Yes
Euphorbia lathyris (Caper spurge) is a non-native California herb in the Euphorbiaceae family, recognized by extreme height and fruit size diagnostic.
Caper spurge is a naturalized biennial found in northwestern California, the Great Valley, central coastal California, southern California, Transverse Ranges, and Peninsular Ranges in disturbed areas at elevations below 200 meters. Flowering throughout the year, this plant produces small greenish flowers in clusters with distinctive four-branched umbel-like arrangements. Growing 50 to 150 centimeters tall with erect, glabrous stems, it has a distinctive leaf arrangement with proximal leaves opposite and four-ranked, and distal leaves arranged in a whorl of four. Its leaves are linear to lanceolate, 5 to 15 centimeters long, sessile and clasping at the base with acute tips. The fruit is a spheric, shallowly lobed capsule 8 to 15 millimeters long, containing brown seeds with a net-like surface.
Identification and appearance
Key characters: 27 sympatric species; extreme height and fruit size diagnostic
Habitat and range
Habitat: Disturbed areas
Elevation: < 200 m
California counties: San Mateo, Monterey, San Luis Obispo, Santa Barbara, Los Angeles, San Diego, Riverside, San Bernardino, Alameda, Siskiyou, Marin, San Francisco, Ventura, Santa Cruz, Mendocino, Orange, Santa Clara, Humboldt, Kern, Stanislaus, Trinity, Yuba, Butte, Sacramento, El Dorado, Contra Costa, Sierra, Solano, Yolo, Napa, Lake, Sonoma, Nevada, San Benito
Outside California: to eastern United States, native to Europe
Bloom period
Euphorbia lathyris blooms All year.
Conservation status
Cal-IPC Yes
How to tell it apart
vs Croton: Euphorbia bleeds milky white latex and packs its flowers into a tiny cup (cyathium) rimmed with nectar glands; Croton has watery sap, stellate or scaly hairs, and ordinary small separate male and female flowers.; vs Stillingia: Euphorbia flowers sit in a gland-bearing cyathium; Stillingia bears its flowers in a spike with a pair of glands flanking each subtending bract and has no cyathium cup.; vs Ditaxis: Euphorbia has latex and the cyathium; Ditaxis has clear sap, 5-parted petaled male and female flowers, and 2-forked (malpighiaceous) hairs.; vs Asclepias: Both ooze milky sap, but Euphorbia's minute flowers cluster in a cyathium and ripen into a 3-lobed capsule; milkweeds have showy 5-parted flowers with a crown and paired follicles of plumed seeds.; vs Polygonum: Prostrate mat spurges leak milky sap when torn and have paired stipules with opposite leaves at the nodes; knotweeds have clear sap and a papery sheath (ocrea) wrapping each node.
Frequently asked questions
Is Euphorbia lathyris native to California?
No. Euphorbia lathyris is not native to California (recorded as not native).
When does Euphorbia lathyris bloom?
Euphorbia lathyris blooms All year.
Where in California does Euphorbia lathyris grow?
Euphorbia lathyris occurs in San Mateo, Monterey, San Luis Obispo, Santa Barbara, Los Angeles, San Diego, Riverside, San Bernardino and other counties, at elevations of < 200 m.
What plant family does Euphorbia lathyris belong to?
Euphorbia lathyris is in the Euphorbiaceae family, genus Euphorbia.
Is Euphorbia lathyris invasive in California?
Euphorbia lathyris is listed by Cal-IPC with an invasiveness rating of Yes.
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.