Taxon Report
Ceanothus decornutus V.T. ParkerNicasio ceanothus |
 © 2014 Vernon Smith |
Taxon Summary
Ceanothus decornutus, commonly known as Nicasio ceanothus, is a perennial shrub in the Rhamnaceae that is found only in California. It occurs within Chaparral, growing at elevations from 235 to 290 meters. Ceanothus decornutus is ranked 1B.2, Plants Rare, Threatened or Endangered in California and Elsewhere; Moderately threatened in California.Classification
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Scientific Name: |
Ceanothus decornutus V.T. Parker |
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Common Name: |
Nicasio ceanothus |
| Family: | Rhamnaceae |
| Element Code: | PDRHA04440 |
| USDA Plants Symbol: | |
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Synonyms/Other Names: |
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Ecology and Life History
| Lifeform: | perennial shrub |
| Blooming Period: Mar-May | Mar-May |
| Elevation: | 235-290 (770-950) |
| General Habitats: | Chaparral |
| Microhabitat: | Clay (sometimes), Rocky, Serpentine |
| Microhabitat Details: |
Conservation Status
| CA Rare Plant Rank: | 1B.2 |
| Global Rank: | G1 |
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State Rank: |
S1 |
| 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: | 2 |
| Element Occurrence Ranks: | |
| Excellent (A) | 0 |
| Good (B) | 0 |
| Fair (C) | 0 |
| Poor (D) | 0 |
| None (X) | 0 |
| Unknown (U) | 2 |
| California Endemic: True | |
| California Counties and Islands: Name (Code) | |
| Marin (MRN) | |
| Quads: Name (Quad Code) | |
| San Geronimo (3812216) | |
Threat List Data from the CNDDB
| Threat List Total: | 2 | |
| EOs with Threat Listed: | Total EOs | % of EOs |
| 1 | 50 % | |
| Non-native plant impacts | 1 | 50% |
| Other | 1 | 50% |
Notes
| Discovered in the 1980’s by Wilma Follette. Similar to C. jepsonii; primarily differs from it in having 5-merous flowers that are white, light blue, or pink. See Madroño 61(4):399-406 (2014) for original description. |
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Threats: |
| Potentially threatened by non-native plants. Possibly threatened by insect herbivory. |
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Taxonomy: |
Selected References
| Proposed Addition to CRPR 1B.2, G1 / S1 (2016) |
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].