Taxon Report

Euphorbia hooveri L.C. Wheeler

Hoover's spurge

Print Report

Taxon Summary

Euphorbia hooveri, commonly known as Hoover's spurge, is a annual herb in the Euphorbiaceae that is found only in California. It occurs within Vernal pools, growing at elevations from 25 to 250 meters. Euphorbia hooveri is ranked 1B.2, Plants Rare, Threatened or Endangered in California and Elsewhere; Moderately threatened in California.

Classification


Scientific Name:	Euphorbia hooveri L.C. Wheeler
Common Name:	Hoover's spurge
Family:	Euphorbiaceae
Element Code:	PDEUP0D150
USDA Plants Symbol:
Synonyms/Other Names:	Chamaesyce hooveri (Wheeler) Koutnik

Ecology and Life History


Lifeform:	annual herb
Blooming Period: (May-Jun)Jul-Sep(Oct)	(May-Jun)Jul-Sep(Oct)
Elevation:	25-250 (80-820)
General Habitats:	Vernal pools
Microhabitat:
Microhabitat Details:

Conservation Status


CA Rare Plant Rank:	1B.2
Global Rank:	G1
State Rank:	S1
State List:	None
Fed List:	FT
Other Status:
CRPR Changes:

Occurrence Data from the CNDDB


Total Occurrences:	29
Element Occurrence Ranks:
Excellent (A)	2
Good (B)	7
Fair (C)	9
Poor (D)	2
None (X)	4
Unknown (U)	5

Location


California Endemic: True
California Counties and Islands: Name (Code)
Butte (BUT), Glenn (GLE), Merced (MER), Stanislaus (STA), Tehama (TEH), Tulare (TUL)
Quads: Name (Quad Code)
Cooperstown (3712065), Hamlin Canyon (3912166), Ivanhoe (3611942), Logandale (3912242), Monson (3611943), Montpelier (3712056), Nord (3912178), Richardson Springs NW (3912188), Turlock Lake (3712055), Turner Ranch (3712026), Vina (3912281)

Threat List Data from the CNDDB


Threat List Total:	12
EOs with Threat Listed:	Total EOs	% of EOs
	23	79 %
Grazing	19	65%
Non-native plant impacts	6	20%
Agriculture	5	17%
Altered flood/tidal/hydrologic regime	4	13%
Foot traffic/trampling	4	13%
Erosion/runoff	3	10%
Biocides	1	3%
Development	1	3%
Disking	1	3%
Other	1	3%
Recreational use (non-ORV)	1	3%
Surface water diversion	1	3%

Notes



Threatened by grazing, agriculture, and non-native plants. See Proceedings of the Biological Society of Washington 53:9 (1940) for original description, Madroño 32(3):187-189 (1985) for alternative nomenclature, and Taxon 55:397-420 (2006) for taxonomic treatment.
Threats:

Taxonomy:

Selected References

Citation California Native Plant Society, Rare Plant Program. 2025. Rare Plant Inventory (online edition, v9.5.1). Website https://www.rareplants.cnps.org [accessed 24 October 2025].