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Dimeresia howellii

Gray

Doublet

G4Apparently Secure Found in 10 roadless areas NatureServe Explorer →
G4Apparently SecureGlobal Rank
UnknownThreat Impact
Identity
Unique IDELEMENT_GLOBAL.2.144998
Element CodePDAST2Z010
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryVascular Plant
Endemicendemic to a single nation
KingdomPlantae
PhylumAnthophyta
ClassDicotyledoneae
OrderAsterales
FamilyAsteraceae
GenusDimeresia
Other Common Names
doublet (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 Date2023-08-25
Change Date2023-08-25
Edition Date2023-08-25
Edition AuthorsGRIES, D, rev. Maybury (2002), rev. Eberly (2023)
Threat ImpactUnknown
Range Extent20,000-200,000 square km (about 8000-80,000 square miles)
Number of Occurrences81 - 300
Rank Reasons
Dimeresia howellii is a diminutive annual herb of the western United States that is known from northeastern California, southeastern Oregon, southwestern Idaho, and northern Nevada. It is most common in the center of its range in Nevada and Oregon, but uncommon in a limited area of California and Idaho. Rangewide threats and trends are unknown but localized threats could include off road vehicles, energy development, agriculture, and recreational activities.
Range Extent Comments
Dimeresia howellii occurs in the western United States in northeastern California (Lassen, Modoc, and Siskiyou Counties) and northwestern Nevada, to Baker County, southern Oregon and southwestern Idaho (Owyhee County) (Idaho Native Plant Society 1993, Skinner 1997, Jepson Flora Project 2023). In California, it is found on the Modoc Plateau and in the Warner Mountains (Jepson Flora Project 2023). Range extent was estimated using herbarium specimens, photo-based observations, and NatureServe Network occurrence data collected between 1983 and 2023 (CNNDB 2023, GBIF 2023, iNaturalist 2023, NatureServe 2023, SEINet 2023).
Occurrences Comments
By applying a 1 km separation distance to herbarium specimens, photo-based observations, and NatureServe Network occurrence data documented between 1983 and 2023, it is estimated that there are roughly 115 occurrences rangewide (CNDDB 2023, GBIF 2023, iNaturalist 2023, NatureServe 2023, SEINet 2023).
Threat Impact Comments
Potential threats to this species include mineral exploration and mining, off road vehicle use, recreational activities, grazing or trampling by livestock, and energy development (Colwell and Sims 2018).
Ecology & Habitat

Habitat

This species is found in open, dry, sandy or gravelly habitats, talus slopes screes, and sagebrush flats on volcanic or serpentine substrates, at elevations ranging from 1,100 to 2,900 meters (Flora of North America Editorial Committee 2006c, Oregon State University 2023).
Terrestrial Habitats
BarrensBare rock/talus/scree
Other Nations (1)
United StatesN4
ProvinceRankNative
IdahoS2Yes
CaliforniaS3Yes
NevadaS4Yes
OregonSNRYes
Threat Assessments
ThreatScopeSeverityTiming
2 - Agriculture & aquacultureUnknownUnknownHigh (continuing)
2.3 - Livestock farming & ranchingUnknownUnknownHigh (continuing)
3 - Energy production & miningUnknownUnknownHigh (continuing)
4 - Transportation & service corridorsUnknownUnknownHigh (continuing)
6 - Human intrusions & disturbanceUnknownUnknownHigh (continuing)
6.1 - Recreational activitiesUnknownUnknownHigh (continuing)

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Plant Characteristics
DurationANNUAL
Economic Value (Genus)No
Roadless Areas (10)
California (7)
AreaForestAcres
Callahan FlowModoc National Forest6,618
Dobie FlatModoc National Forest15,079
DryModoc National Forest7,726
Knox Mtn.Modoc National Forest5,975
LavasModoc National Forest25,864
Mt. HoffmanModoc National Forest9,780
SoldierModoc National Forest10,102
Nevada (2)
AreaForestAcres
East Fork QuinnHumboldt-Toiyabe National Forest30,977
McaffieHumboldt-Toiyabe National Forest26,110
Oregon (1)
AreaForestAcres
Crane MountainFremont National Forest23,096
References (12)
  1. California Natural Diversity Database (CNDDB). 2023. RareFind Version 5.2.14. California Department of Fish and Game, Sacramento.
  2. Colwell, A., and A. Sims. 2018. USFS Potential Species of Conservation Concern Profile: <i>Dimeresia howellii</i>. California Native Plant Society. Online. Available: https://rareplantfiles.cnps.org/scc/DimeresiaHowelliiSpProfileSCC20180424.pdf.
  3. Flora of North America Editorial Committee (FNA). 2006c. Flora of North America north of Mexico. Vol. 21. Magnoliophyta: Asteridae, part 8: Asteraceae, part 3. Oxford Univ. Press, New York. xxii + 616 pp.
  4. Global Biodiversity Information Facility (GBIF). 2023. Global Biodiversity Information Facility (GBIF) data portal. Online. Available: https://www.gbif.org/ (accessed 2023).
  5. Hickman, J. C., ed. 1993. The Jepson manual: Higher plants of California. University of California Press, Berkeley, CA. 1400 pp.
  6. Idaho Native Plant Society. 1993. Federal candidate (C1 and C2) and listed rare plants of Idaho. unpaginated.
  7. iNaturalist. 2023. Online. Available: https://www.inaturalist.org (accessed 2023).
  8. 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.
  9. NatureServe. 2023. NatureServe Network Biodiversity Location Data. NatureServe, Arlington, Virginia.
  10. Oregon State University (OSU). 2023. Oregon Flora website. Oregon State University Herbarium at Oregon State University. Online. Available: https://oregonflora.org/ (accessed 2023).
  11. 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.
  12. Southwest Environmental Information Network (SEINet). 2023. Collections Databases. Online. Available: https://swbiodiversity.org/seinet/collections/index.php (accessed 2023).