Taxon Report
Helianthella castanea GreeneDiablo helianthella |
 © 2013 Christopher Bronny |
Taxon Summary
Helianthella castanea, commonly known as Diablo helianthella, is a perennial herb in the Asteraceae that is found only in California. It occurs within Broadleafed upland forest, Chaparral, Cismontane woodland, Coastal scrub, Riparian woodland, and Valley and foothill grassland, growing at elevations from 60 to 1300 meters. Helianthella castanea is ranked 1B.2, Plants Rare, Threatened or Endangered in California and Elsewhere; Moderately threatened in California.Classification
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Scientific Name: |
Helianthella castanea Greene |
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Common Name: |
Diablo helianthella |
| Family: | Asteraceae |
| Element Code: | PDAST4M020 |
| USDA Plants Symbol: | HECA2 |
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Synonyms/Other Names: |
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Ecology and Life History
| Lifeform: | perennial herb |
| Blooming Period: Mar-Jun | Mar-Jun |
| Elevation: | 60-1300 (195-4265) |
| General Habitats: | Broadleafed upland forest, Chaparral, Cismontane woodland, Coastal scrub, Riparian woodland, Valley and foothill grassland |
| Microhabitat: | Rocky (usually) |
| Microhabitat Details: | Azonal soil, often partial Shade |
Conservation Status
| CA Rare Plant Rank: | 1B.2 |
| Global Rank: | G2 |
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State Rank: |
S2 |
| State List: | None |
| Fed List: | None |
| Other Status: | BLM_S; SB_CalBG/RSABG |
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CRPR Changes: |
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Occurrence Data from the CNDDB
| Total Occurrences: | 107 |
| Element Occurrence Ranks: | |
| Excellent (A) | 11 |
| Good (B) | 35 |
| Fair (C) | 22 |
| Poor (D) | 2 |
| None (X) | 1 |
| Unknown (U) | 36 |
| California Endemic: True | |
| California Counties and Islands: Name (Code) | |
| Alameda (ALA), Contra Costa (CCA), Marin (MRN)*, San Francisco (SFO)*, San Mateo (SMT) | |
| Quads: Name (Quad Code) | |
| Antioch South (3712187), Benicia (3812212), Briones Valley (3712282), Cedar Mtn. (3712155), Clayton (3712188), Diablo (3712178), Dublin (3712168), Hayward (3712261), Hunters Point (3712263), Las Trampas Ridge (3712271), Oakland East (3712272)*, Richmond (3712283), San Francisco South (3712264), San Rafael (3712285)*, Tassajara (3712177), Walnut Creek (3712281) | |
Threat List Data from the CNDDB
| Threat List Total: | 12 | |
| EOs with Threat Listed: | Total EOs | % of EOs |
| 55 | 51 % | |
| Grazing | 25 | 23% |
| Road/trail construction/maint. | 18 | 16% |
| Foot traffic/trampling | 17 | 15% |
| Development | 12 | 11% |
| Recreational use (non-ORV) | 10 | 9% |
| Other | 8 | 7% |
| Improper burning regime | 8 | 7% |
| Erosion/runoff | 6 | 5% |
| Non-native plant impacts | 6 | 5% |
| Insufficient population/stand size | 1 | 0% |
| Vandalism/dumping/litter | 1 | 0% |
| Wood cutting or brush clearing | 1 | 0% |
Citation
California Native Plant Society, Rare Plant Program. 2025. Rare Plant Inventory (online edition, v9.5.1). Website https://www.rareplants.cnps.org [accessed 7 November 2025].