Taxon Report
Ambrosia pumila (Nutt.) GraySan Diego ambrosia |
 © 2010 Benjamin Smith |
Taxon Summary
Ambrosia pumila, commonly known as San Diego ambrosia, is a perennial rhizomatous herb in the Asteraceae that is found in California and elsewhere. It occurs within Chaparral, Coastal scrub, Valley and foothill grassland, and Vernal pools, growing at elevations from 20 to 415 meters. Ambrosia pumila is ranked 1B.1, Plants Rare, Threatened or Endangered in California and Elsewhere; Seriously threatened in California.Classification
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Scientific Name: |
Ambrosia pumila (Nutt.) Gray |
|
Common Name: |
San Diego ambrosia |
| Family: | Asteraceae |
| Element Code: | PDAST0C0M0 |
| USDA Plants Symbol: | AMPU4 |
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Synonyms/Other Names: |
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Ecology and Life History
| Lifeform: | perennial rhizomatous herb |
| Blooming Period: Apr-Oct | Apr-Oct |
| Elevation: | 20-415 (65-1360) |
| General Habitats: | Chaparral, Coastal scrub, Valley and foothill grassland, Vernal pools |
| Microhabitat: | Alkaline (sometimes), Clay (sometimes), Disturbed areas (often), Loam (sometimes), Sandy (sometimes) |
| Microhabitat Details: |
Conservation Status
| CA Rare Plant Rank: | 1B.1 |
| Global Rank: | G1 |
|
State Rank: |
S1 |
| State List: | None |
| Fed List: | FE |
| Other Status: | SB_CRES |
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CRPR Changes: |
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Occurrence Data from the CNDDB
| Total Occurrences: | 61 |
| Element Occurrence Ranks: | |
| Excellent (A) | 2 |
| Good (B) | 6 |
| Fair (C) | 9 |
| Poor (D) | 7 |
| None (X) | 21 |
| Unknown (U) | 16 |
| California Endemic: False | |
| California Counties and Islands: Name (Code) | |
| Riverside (RIV), San Diego (SDG) | |
| Quads: Name (Quad Code) | |
| Aguanga (3311647), Alberhill (3311764), Bachelor Mtn. (3311751), Bonsall (3311732), Del Mar (3211782), El Cajon (3211678), Escondido (3311711), Imperial Beach (3211751), Jamul Mountains (3211668), La Jolla (3211772), La Mesa (3211771), Lake Elsinore (3311763), National City (3211761), Oceanside (3311724), Rancho Santa Fe (3311712), Riverside West (3311784)*, San Luis Rey (3311723), Temecula (3311742), Vail Lake (3311648) | |
Threat List Data from the CNDDB
| Threat List Total: | 17 | |
| EOs with Threat Listed: | Total EOs | % of EOs |
| 54 | 89 % | |
| Development | 43 | 70% |
| Non-native plant impacts | 29 | 47% |
| Foot traffic/trampling | 15 | 24% |
| Road/trail construction/maint. | 15 | 24% |
| Other | 14 | 22% |
| Vandalism/dumping/litter | 8 | 13% |
| Wood cutting or brush clearing | 7 | 11% |
| Recreational use (non-ORV) | 6 | 9% |
| Erosion/runoff | 5 | 8% |
| ORV activity | 4 | 6% |
| Disking | 4 | 6% |
| Agriculture | 2 | 3% |
| Grazing | 2 | 3% |
| Mining | 1 | 1% |
| Altered flood/tidal/hydrologic regime | 1 | 1% |
| Biocides | 1 | 1% |
| Over-collecting/poaching | 1 | 1% |
Citation
California Native Plant Society, Rare Plant Program. 2025. Rare Plant Inventory (online edition, v9.5.1). Website https://www.rareplants.cnps.org [accessed 1 February 2025].