Taxon Report
Euphorbia exstipulata Engelm. var. exstipulataClark Mountain spurge |
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Taxon Summary
Euphorbia exstipulata var. exstipulata, commonly known as Clark Mountain spurge, is a annual herb in the Euphorbiaceae that is found in California and elsewhere. It occurs within Mojavean desert scrub, growing at elevations from 1280 to 2000 meters. Euphorbia exstipulata var. exstipulata is ranked 2B.1, Plants Rare, Threatened, or Endangered in California, But More Common Elsewhere; Seriously threatened in California.Classification
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Scientific Name: |
Euphorbia exstipulata Engelm. var. exstipulata |
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Common Name: |
Clark Mountain spurge |
| Family: | Euphorbiaceae |
| Element Code: | PDEUP0Q0P1 |
| USDA Plants Symbol: | |
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Synonyms/Other Names: |
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Ecology and Life History
| Lifeform: | annual herb |
| Blooming Period: Sep | Sep |
| Elevation: | 1280-2000 (4200-6560) |
| General Habitats: | Mojavean desert scrub |
| Microhabitat: | |
| Microhabitat Details: |
Conservation Status
| CA Rare Plant Rank: | 2B.1 |
| Global Rank: | G5T5? |
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State Rank: |
S2 |
| State List: | None |
| Fed List: | None |
| Other Status: | SB_CalBG/RSABG |
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CRPR Changes: |
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Occurrence Data from the CNDDB
| Total Occurrences: | 10 |
| Element Occurrence Ranks: | |
| Excellent (A) | 0 |
| Good (B) | 2 |
| Fair (C) | 0 |
| Poor (D) | 0 |
| None (X) | 0 |
| Unknown (U) | 8 |
| California Endemic: False | |
| California Counties and Islands: Name (Code) | |
| San Bernardino (SBD) | |
| Quads: Name (Quad Code) | |
| Castle Peaks (3511532), Clark Mtn. (3511555), Hart Peak (3511531), Ivanpah (3511533), Mescal Range (3511545), Mineral Hill (3511544), Pinto Valley (3511523) | |
Threat List Data from the CNDDB
| Threat List Total: | 5 | |
| EOs with Threat Listed: | Total EOs | % of EOs |
| 4 | 40 % | |
| Mining | 4 | 40% |
| ORV activity | 3 | 30% |
| Vandalism/dumping/litter | 2 | 20% |
| Non-native animal impacts | 1 | 10% |
| Development | 1 | 10% |
Citation
California Native Plant Society, Rare Plant Program. 2025. Rare Plant Inventory (online edition, v9.5.1). Website https://www.rareplants.cnps.org [accessed 3 November 2025].