Taxon Report
Phacelia greenei J.T. HowellScott Valley phacelia |
 © 2011 Steve Matson |
Taxon Summary
Phacelia greenei, commonly known as Scott Valley phacelia, is a annual herb in the Hydrophyllaceae that is found only in California. It occurs within Closed-cone coniferous forest, Lower montane coniferous forest, Subalpine coniferous forest, and Upper montane coniferous forest, growing at elevations from 800 to 2440 meters. Phacelia greenei is ranked 1B.2, Plants Rare, Threatened or Endangered in California and Elsewhere; Moderately threatened in California.Classification
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Scientific Name: |
Phacelia greenei J.T. Howell |
|
Common Name: |
Scott Valley phacelia |
| Family: | Hydrophyllaceae |
| Element Code: | PDHYD0C1V0 |
| USDA Plants Symbol: | PHGR2 |
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Synonyms/Other Names: |
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Ecology and Life History
| Lifeform: | annual herb |
| Blooming Period: Apr-Jun | Apr-Jun |
| Elevation: | 800-2440 (2625-8005) |
| General Habitats: | Closed-cone coniferous forest, Lower montane coniferous forest, Subalpine coniferous forest, Upper montane coniferous forest |
| Microhabitat: | Serpentine |
| Microhabitat Details: |
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; USFS_S |
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CRPR Changes: |
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Occurrence Data from the CNDDB
| Total Occurrences: | 24 |
| Element Occurrence Ranks: | |
| Excellent (A) | 5 |
| Good (B) | 10 |
| Fair (C) | 3 |
| Poor (D) | 0 |
| None (X) | 0 |
| Unknown (U) | 6 |
| California Endemic: True | |
| California Counties and Islands: Name (Code) | |
| Siskiyou (SIS), Trinity (TRI) | |
| Quads: Name (Quad Code) | |
| Callahan (4112237), China Mtn. (4112245), Duzel Rock (4112256), Eaton Peak (4112238), Fort Jones (4112257), Greenview (4112258), McConaughy Gulch (4112247), Scott Mountain (4112236), South China Mtn. (4112235), Yreka (4112266) | |
Threat List Data from the CNDDB
| Threat List Total: | 10 | |
| EOs with Threat Listed: | Total EOs | % of EOs |
| 16 | 67 % | |
| Other | 7 | 29% |
| Road/trail construction/maint. | 6 | 25% |
| Logging | 5 | 20% |
| Mining | 5 | 20% |
| Grazing | 5 | 20% |
| ORV activity | 2 | 8% |
| Recreational use (non-ORV) | 1 | 4% |
| Improper burning regime | 1 | 4% |
| Biocides | 1 | 4% |
| Foot traffic/trampling | 1 | 4% |
Notes
| Known only in the vicinity of Scott Valley. |
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Threats: |
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Possibly threatened by mining. |
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Taxonomy: |
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Similar to the more widespread P. humilis which is sometimes mistaken for P. greenei outside of Scott Valley; differentiated from P. humilis in having glabrous vs. short-hairy stamens in addition to other characters. |
Selected References
| Phacelia greenei account for potential Species of Conservation Concern evaluation (2020) |
Citation
California Native Plant Society, Rare Plant Program. 2025. Rare Plant Inventory (online edition, v9.5.1). Website https://www.rareplants.cnps.org [accessed 19 November 2025].