CNPS

CNPS Rare Plant Inventory



Taxon Details

Hosackia yollabolliensis

Yolla Bolly Mtns. bird's-foot trefoil

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Photo of Hosackia yollabolliensis
2013 Shasta-Trinity National Forest 		Photo of Hosackia yollabolliensis
©2017 Belinda Lo 		Photo of Hosackia yollabolliensis
©2017 Belinda Lo

Taxon Summary:

Hosackia yollabolliensis, commonly known as Yolla Bolly Mtns. bird's-foot trefoil, is a perennial herb in the Fabaceae that is found only in California. It occurs within Meadows and seeps, and Upper montane coniferous forest (openings), growing at elevations from 1645 to 2135 meters. Hosackia yollabolliensis is ranked 1B.2, Plants Rare, Threatened or Endangered in California and Elsewhere; Moderately threatened in California.

  Classification

Scientific Name:
Hosackia yollabolliensis (Munz) D.D. Sokoloff
Common Name:
Yolla Bolly Mtns. bird's-foot trefoil
Family: Fabaceae
Element Code: PDFAB2A1F0
USDA Plants Symbol:
Synonyms/Other Names:
Name Status: JEF, FNA, POWO,
IPNI, Tropicos

  Conservation Status

CA Rare Plant Rank: 1B.2
Fed List: None
State List: None
Global Rank: G2
State Rank:
 S2
Other Status: SB_CalBG/RSABG
CRPR Changes:
changed from 4.3 to 1B.2 on 2013-08-21
Add Date: 1974-01-01
Date Edited: 2025-06-03

  Ecology and Life History

Lifeform: perennial herb
Blooming Period: Jun-Aug
JFMAMJJASOND
Elevation:
1645 - 2135 meters
5395 - 7005 feet
General Habitats:
  • Meadows and seeps
  • Upper montane coniferous forest (openings)
Microhabitat Details: dry barren exposed slopes
Microhabitat:
  • Dry
  • Gravelly (often)
  • Slopes

  Notes

Notes:
Previously CRPR 4.3; rarer than originally thought.
Threats:
Threatened by vehicles, conifer encrouchment, and non-native plants. Potentially threatened by climate shifts. Possibly threatened by trampling and grazing.
Taxonomy:

  Threat List Data from the CNDDB

Threat List Total: 2
Total EOs % of EOs
EOs with Threat Listed: 2 18 %
THREAT LIST:
Other 2 18%
ORV activity 1 9%

  Occurrence Data from the CNDDB

Total Occurrences: 11
Element Occurrence Ranks:
A B C D X U
0 0 0 0 0 11
Occurrence Status:
Historical >20 Years 6
Recent <=20 Years 5
Presence:
Presumed Extant 11
Possibly Extirpated 0
Presumed Extirpated 0

  Location

California Endemic:
California Island:
States: Name (Code)
California (CA)
California Counties and Islands: Name (Code)
Humboldt (HUM), Trinity (TRI)
Quads: Name (Quad Code)
Black Rock Mtn. (4012321), Blake Mountain (4012355), Dinsmore (4012345), Forest Glen (4012333), Hyampom (4012354), North Yolla Bolly (4012228), Sims Mountain (4012365), Sportshaven (4012344)
Notes:
Definitions of codes following a county and/or quad:
* Presumed extirpated
(?) Occurrence confirmed, but possibly extirpated
Quad and county data is imported from the CNDDB. Species may be present in other areas where conditions are favorable. These data should NOT be substituted for pre-project review or for on-site surveys.
Regional Map

  Map

Presumed Extant
Click on quad for name. Hold Shift Key to use mouse scroll wheel

  Selected References

CNPS Status Review: Proposed Change from California Rare Plant Rank 4.3, G3 / S3.3 to 1B.2, G2 / S2
Original Description: Aliso 3:117 (1955)
Revised Nomenclature: Kew Bulletin 55(4):1010 (2000) 
Species Account: Hosackia yollabolliensis profile for potential Species of Conservation Concern evaluation (2022)

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Suggested Citation:
California Native Plant Society, Rare Plant Program. 2025. Rare Plant Inventory (online edition, v9.5.1). Website https://www.rareplants.cnps.org [accessed 15 July 2025].
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