Euphorbia hooveri
Hoover's spurge, Hoover's Spurge
(c) Trevor Van Loon, some rights reserved (CC BY) · licence
Family: Euphorbiaceae · Type: Herb · Native
Conservation status: CNPS 1B.2 · Threatened
Euphorbia hooveri (Hoover's spurge) is a native California herb in the Euphorbiaceae family, recognized by deeply lobed appendages and undivided styles diagnostic.
Hoover's spurge is a rare (CNPS 1B.2) California native annual found in the Great Valley bioregion in Butte, Tehama, and Tulare counties within vernal pool habitats at elevations below 250 meters. Flowering from July to September, this plant produces small white petal-like appendages surrounding delicate cyathia with round glands. Growing with prostrate to decumbent stems that repeatedly fork and spread in a two-faced pattern, it reaches a low, spreading form across the ground. Its opposite leaves are tiny, approximately 2 to 5 millimeters long, rounded with asymmetric bases and minutely spiny-edged, creating a delicate texture. The fruit is a small spheric, lobed structure approximately 1.5 to 2 millimeters long, producing white, widely four-angled seeds.
Identification and appearance
Key characters: 16 sympatric species; deeply lobed appendages and undivided styles diagnostic
Habitat and range
Habitat: Vernal pools
Elevation: < 250 m
California counties: Tulare, Stanislaus, Tehama, Butte
Bloom period
Euphorbia hooveri blooms Jul-Sep.
Conservation status
CNPS 1B.2 · Threatened
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 hooveri native to California?
Yes. Euphorbia hooveri is native to California (recorded as native).
When does Euphorbia hooveri bloom?
Euphorbia hooveri blooms Jul-Sep.
Where in California does Euphorbia hooveri grow?
Euphorbia hooveri occurs in Tulare, Stanislaus, Tehama, Butte, at elevations of < 250 m.
What plant family does Euphorbia hooveri belong to?
Euphorbia hooveri is in the Euphorbiaceae family, genus Euphorbia.
Is Euphorbia hooveri rare or endangered?
Euphorbia hooveri carries California Rare Plant Rank 1B.2, state rank S1.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · CNPS Rare Plant Inventory · Index of California Plant Names · CalPhotos · CDFW CNDDB
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.