Roadless Areas
Home/Species/ Butterworth's Buckwheat

Eriogonum butterworthianum

J.T. Howell

Butterworth's Buckwheat

G1Critically Imperiled Found in 2 roadless areas NatureServe Explorer →
G1Critically ImperiledGlobal Rank
UnknownThreat Impact
Identity
Unique IDELEMENT_GLOBAL.2.143008
Element CodePDPGN080X0
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryVascular Plant
Endemicendemic to a single state or province
KingdomPlantae
PhylumAnthophyta
ClassDicotyledoneae
OrderPolygonales
FamilyPolygonaceae
GenusEriogonum
Other Common Names
Butterworth's Wild Buckwheat (EN)
Concept Reference
Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.
Conservation Status
Rank Method Rank calculation - Biotics v2
Review Date2025-09-03
Change Date2025-09-03
Edition Date2025-09-03
Edition AuthorsD. Gries, rev. R. Bittman (2005, 2025), rev. Eberly (2025)
Threat ImpactUnknown
Range Extent<100 square km (less than about 40 square miles)
Number of Occurrences1 - 5
Rank Reasons
Eriogonum butterworthianum is a subshrub known from three occurrences in Monterey County, California in the western United States. It is restricted to sandstone outcrops of the Vaqueros Formation The range extent is extremely small (less than 3 sq km). Threats include recreational activities like hiking and rocking climbing and wildfire. All known occurrences are on the Los Padres National Forest. Surveys are needed to better document threats and population sizes.
Range Extent Comments
Eriogonum butterworthianum occurs in the western United States, where it is endemic to sandstone outcrops of the eastern Santa Lucia Range of Monterey County in central California (FNA 2005). It occurs in one California Floristic Province, the Outer South Coast Range (Jepson Flora Project 2025). Range extent was estimated using NatureServe Network occurrence data (CNDDB 2025).
Occurrences Comments
There are four occurrences documented, but one occurs in an abnormal habitat and thus the identification should be reviewed. That occurrence is not included in this assessment.
Threat Impact Comments
This species is threatened by recreational activities including rock climbing and hiking (CNDDB 2025). Aside from one occurrence located on private land with an uncertain identification, the remaining occurrences were burned in a 2008 wildfire.
Ecology & Habitat

Habitat

This species grows in the cracks and crevices of dry sandstone (Vaqueros Formation) outcrops within chaparral and oak and conifer woodland communities and elevations of up to 715 m (CNDDB 2025, Jepson Flora Project 2025). Common associates include Castilleja foliosa and Mimulus aurantiacus (Stephenson and Calcarone 1999).
Terrestrial Habitats
Forest/WoodlandForest - MixedWoodland - MixedShrubland/chaparralBare rock/talus/scree
Other Nations (1)
United StatesN1
ProvinceRankNative
CaliforniaS1Yes
Threat Assessments
ThreatScopeSeverityTiming
6 - Human intrusions & disturbanceLarge (31-70%)UnknownHigh (continuing)
6.1 - Recreational activitiesLarge (31-70%)UnknownHigh (continuing)
7 - Natural system modificationsUnknownUnknownHigh (continuing)
7.1 - Fire & fire suppressionUnknownUnknownHigh (continuing)
7.1.1 - Increase in fire frequency/intensityUnknownUnknownHigh (continuing)

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Plant Characteristics
DurationPERENNIAL
Economic Value (Genus)No
Roadless Areas (2)
California (2)
AreaForestAcres
Bear MountainLos Padres National Forest913
Chalk PeakLos Padres National Forest7,472
References (10)
  1. CalFlora. 2005. Information on California plants for education, research and conservation. Berkeley, California: The CalFlora Database [web application]. Available: http://www.calflora.org/. (Accessed 2005)
  2. California Native Plant Society (CNPS). 2001. Inventory of Rare and Endangered Plants of California (sixth edition). Rare Plant Scientific Advisory Committee, David P. Tibor, Convening Editor. California Native Plant Society. Sacramento, CA. x + 388pp.
  3. California Natural Diversity Database (CNDDB). 2025. RareFind Version 5.3.0. California Department of Fish and Game, Sacramento.
  4. Flora of North America Editorial Committee (FNA). 2005. Flora of North America north of Mexico. Vol. 5. Magnoliophyta: Caryophyllidae: Caryophyllales, Polygonales, and Plumbaginales. Oxford Univ. Press, New York. vii + 656 pp.
  5. Hickman, J. C., ed. 1993. The Jepson manual: Higher plants of California. University of California Press, Berkeley, CA. 1400 pp.
  6. Jepson Flora Project (eds.) 2025. Jepson eFlora. Online. Available: https://ucjeps.berkeley.edu/eflora/ (accessed 2025).
  7. Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.
  8. Munz, P.A. 1968. Supplement to a California flora. Univ. California Press. Berkeley. 224 pp.
  9. Skinner, M.W., and B.M. Pavlik, eds. 1997 (1994). Inventory of rare and endangered vascular plants of California. 1997 Electronic Inventory Update of 1994 5th edition, California Native Plant Society, Special Publication No. 1, Sacramento.
  10. Stephenson, J. R., and G. M. Calcarone. 1999. Southern California mountains and foothills assessment: habitat and species conservation issues. General Technical Report GTR-PSW-175. Albany, CA: Pacific Southwest Research Station, Forest Service, U.S. Department of Agriculture. 402 pp.