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Draba howellii

S. Wats.

Howell's Whitlow-grass

G4Apparently Secure Found in 9 roadless areas NatureServe Explorer →
G4Apparently SecureGlobal Rank
LowThreat Impact
Identity
Unique IDELEMENT_GLOBAL.2.157520
Element CodePDBRA11150
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryVascular Plant
Endemicendemic to a single nation
KingdomPlantae
PhylumAnthophyta
ClassDicotyledoneae
OrderCapparales
FamilyBrassicaceae
GenusDraba
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 Date2024-05-21
Change Date1991-02-08
Edition Date2024-05-21
Edition AuthorsSoteropoulos, Ferguson, and Bittman (2024)
Threat ImpactLow
Range Extent5000-20,000 square km (about 2000-8000 square miles)
Number of Occurrences21 - 80
Rank Reasons
Draba howellii is a small, perennial herb in rocky crevices with a limited range occurring in the Klamath Range bioregion in northwestern California and southwestern Oregon in the western United States. There are 29 occurrences documented within the past 40 years and many more considered historical which may persist. Though threats are not reported, they are likely low given the species' remote habitats. Monitoring of populations should be conducted to improve our understanding of reproduction, plant abundance, threats, and trends, as well as continuing conservation measures to protect the species.
Range Extent Comments
Draba howellii occurs in the western United States in northwestern California (Del Norte, Humboldt, Shasta, Siskiyou and Trinity Counties) and southwestern Oregon (Josephine County) in the Klamath Range bioregion (Kauppinen and Sims 2022). Range extent was estimated to be 12,348 square kilometers using herbarium specimens, photo-based observations, and NatureServe Network occurrence data documented between 1983 and 2024 (GBIF 2024, iNaturalist 2024, NatureServe 2024, SEINet 2024).
Occurrences Comments
By applying a 1 km separation distance to herbarium specimens, photo-based observations, and NatureServe Network occurrence data documented between 1983 and 2024, it is estimated that there are 29 occurrences rangewide (GBIF 2024, iNaturalist 2024, NatureServe 2024, SEINet 2024). Many occurrences are historical, but without surveys the persistence of plants at them is unknown.
Threat Impact Comments
Though threats are poorly characterized, this species occurs in remote areas with low threat levels (Ferguson and Bittman, pers. comm., 2024).
Ecology & Habitat

Habitat

Draba howellii grows in "rocky summits, cracks in granite walls, rock crevices" (FNA 2010).
Terrestrial Habitats
Bare rock/talus/screeCliff
Other Nations (1)
United StatesNNR
ProvinceRankNative
CaliforniaS4Yes
OregonS2Yes
Threat Assessments
ThreatScopeSeverityTiming
No known threats———

—

Plant Characteristics
DurationPERENNIAL
Economic Value (Genus)No
Roadless Areas (9)
California (9)
AreaForestAcres
Blue Creek Rare ISix Rivers National Forest12,134
Castle Crags AShasta-Trinity National Forest113
Castle Crags BShasta-Trinity National Forest1,619
Lake EleanorShasta-Trinity National Forest397
Little French CShasta-Trinity National Forest11,529
PattisonShasta-Trinity National Forest29,299
SnoozerKlamath National Forest23,414
Weaver BallyShasta-Trinity National Forest829
West GirardShasta-Trinity National Forest37,516
References (11)
  1. Bittman, Roxanne. Personal Communication. Botanist, California Natural Diversity Database, Sacramento, Calif.
  2. Ferguson, Katie. Personal communication. Rare Plant Botanist. California Natural Diversity Database, Department of Fish and Wildlife, Sacramento.
  3. Flora of North America Editorial Committee (FNA). 2010. Flora of North America north of Mexico. Vol. 7. Magnoliophyta: Salicaceae to Brassicaceae. Oxford University Press, New York. xxii + 797 pp.
  4. Global Biodiversity Information Facility (GBIF). 2024. Global Biodiversity Information Facility (GBIF) data portal. Online. Available: https://www.gbif.org/ (accessed 2024).
  5. Hickman, J. C., ed. 1993. The Jepson manual: Higher plants of California. University of California Press, Berkeley, CA. 1400 pp.
  6. iNaturalist. 2024. Online. Available: https://www.inaturalist.org (accessed 2024).
  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. Kauppinen, S. and A. E. Sims. 2022. Plant Species Evaluation Form: <i>Draba howellii </i>Wats. (Howell's Draba). California Native Plant Society. Online. Available: https://rareplantfiles.cnps.org/scc/DrabaHowelliiSpProfileSCC20180711.pdf Accessed May 21, 2024.
  9. NatureServe. 2024. NatureServe Network Biodiversity Location Data. NatureServe, Arlington, Virginia.
  10. 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.
  11. Southwest Environmental Information Network (SEINet). 2024. Collections Databases. Online. Available: https://swbiodiversity.org/seinet/collections/index.php (accessed 2024).