Euphorbia oblongata
Eggleaf spurge
(c) Don Loarie, some rights reserved (CC BY) · licence
Family: Euphorbiaceae · Type: Herb · Not Native
Conservation status: Cal-IPC Yes
Euphorbia oblongata (Eggleaf spurge) is a non-native California herb in the Euphorbiaceae family, recognized by large size and tubercled fruits diagnostic.
Eggleaf spurge is a naturalized perennial herb found in northwestern California, Sierra Nevada foothills, Central Valley, San Francisco Bay Area, and Central Coast in disturbed areas at elevations below 900 meters. Flowering from May to September, this plant produces small yellow-green flowers in dense umbel-like clusters with leafy bracts. Growing with several stems 30 to 80 centimeters tall that are densely hairy, it spreads from the base with distinctive branching. Its leaves are oblong to elliptic, 4 to 6.5 centimeters long, with finely toothed edges and rounded bases, arranged alternately on the lower stem and forming a single whorl near the top. The fruit is a spheric, lobed structure 3 to 4.5 millimeters long, containing smooth brown seeds with a distinctive knob.
Identification and appearance
Key characters: 19 sympatric species; large size and tubercled fruits diagnostic
Habitat and range
Habitat: Disturbed areas
Elevation: < 900 m
California counties: Amador, Calaveras, Tehama, Contra Costa, Santa Clara, San Mateo, Marin, Tuolumne, El Dorado, Solano, Sonoma, Yolo, Santa Cruz, San Luis Obispo, Butte, Shasta, Humboldt, Mendocino, Alameda, Sacramento, Mariposa, Siskiyou, Nevada, Placer, San Joaquin, Lake, Napa, Monterey
Outside California: native to Europe
Bloom period
Euphorbia oblongata blooms May-Sep.
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 oblongata native to California?
No. Euphorbia oblongata is not native to California (recorded as not native).
When does Euphorbia oblongata bloom?
Euphorbia oblongata blooms May-Sep.
Where in California does Euphorbia oblongata grow?
Euphorbia oblongata occurs in Amador, Calaveras, Tehama, Contra Costa, Santa Clara, San Mateo, Marin, Tuolumne and other counties, at elevations of < 900 m.
What plant family does Euphorbia oblongata belong to?
Euphorbia oblongata is in the Euphorbiaceae family, genus Euphorbia.
Is Euphorbia oblongata invasive in California?
Euphorbia oblongata 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.