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Home/Species/ Stipulate Trefoil

Hosackia stipularis

Benth.

Stipulate Trefoil

G4Apparently Secure Found in 8 roadless areas NatureServe Explorer →
G4Apparently SecureGlobal Rank
UnknownThreat Impact
Identity
Unique IDELEMENT_GLOBAL.2.161055
Element CodePDFAB2A180
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryVascular Plant
Endemicendemic to a single nation
KingdomPlantae
PhylumAnthophyta
ClassDicotyledoneae
OrderFabales
FamilyFabaceae
GenusHosackia
Synonyms
Lotus stipularis(Benth.) Greene
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.
Taxonomic Comments
FNA (2023, vol. 11) recognizes Lotus as native to Eurasia, with taxa native to North American treated as Acmispon or Hosackia. FNA (2023, vol. 11) treats Lotus stipularis in the genus Hosackia as H. stipularis.
Conservation Status
Rank Method Rank calculation - Biotics v2
Review Date2026-01-20
Change Date2026-01-20
Edition Date2026-01-20
Edition AuthorsSoteropoulos (2026)
Threat ImpactUnknown
Range Extent20,000-200,000 square km (about 8000-80,000 square miles)
Number of Occurrences81 - 300
Rank Reasons
This taxon is a perennial herb found in open pine forests, streambeds, ditches, serpentine soils, montane areas, thickets, and chaparral, including disturbed habitats such as clearcut or logged forests. It occurs in the western United States from southeastern Oregon and California. There are over 100 occurrences, which face threats from development, rights-of-way maintenance, logging, recreational activities, invasive species, and insect herbivory and seed predation. Little is known about trends, but with a large range extent and large number of occurrences, abundant habitat, and broad habitat preferences, this taxon is considered apparently secure.
Range Extent Comments
This taxon occurs in the western United States from southeastern Oregon and California (FNA 2023, Jepson Flora Project 2026, OSU 2026). Range extent was estimated to be over 110,000 square kilometers using herbarium specimens, photo-based observations, and NatureServe Network occurrence data documented between 1994 and 2025 (RARECAT 2025, GBIF 2026, iNaturalist 2026, NatureServe 2026, SEINet 2026). See each of the varieties for more information.
Occurrences Comments
By applying a 1 km separation distance to herbarium specimens, photo-based observations, and NatureServe Network occurrence data documented between 1994 and 2025, it is estimated that there are over 110 occurrences rangewide (RARECAT 2025, GBIF 2026, iNaturalist 2026, NatureServe 2026, SEINet 2026).
Threat Impact Comments
Although threats are not widely documented, this taxon is threatened by development, rights-of-way maintenance, logging, recreational activities (especially off-road vehicles), invasive species, and insect herbivory and seed predation, though there is insufficient data, including anecdotal accounts, to understand scope and severity of threats for this taxon (NatureServe 2025).
Ecology & Habitat

Habitat

This taxon grows in open pine forests, streambeds, ditches, serpentine soils, montane areas, thickets, and chaparral, including disturbed habitats such as clearcut or logged forests (FNA 2023, OSU 2026).

Reproduction

This taxon flowers in spring to early summer (FNA 2023).
Terrestrial Habitats
Forest/WoodlandForest - ConiferWoodland - ConiferShrubland/chaparral
Other Nations (1)
United StatesN4
ProvinceRankNative
CaliforniaSNRYes
OregonS2Yes
Threat Assessments
ThreatScopeSeverityTiming
1 - Residential & commercial developmentUnknownUnknownHigh (continuing)
4 - Transportation & service corridorsUnknownUnknownHigh (continuing)
5 - Biological resource useUnknownUnknownHigh (continuing)
5.3 - Logging & wood harvestingUnknownUnknownHigh (continuing)
8 - Invasive & other problematic species, genes & diseasesUnknownUnknownHigh (continuing)
8.1 - Invasive non-native/alien species/diseasesUnknownUnknownHigh (continuing)
8.1.1 - Unspecified speciesUnknownUnknownHigh (continuing)
8.2 - Problematic native species/diseasesUnknownUnknownHigh (continuing)
8.2.1 - Unspecified speciesUnknownUnknownHigh (continuing)

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Plant Characteristics
DurationPERENNIAL
Economic Value (Genus)No
Roadless Areas (8)
California (8)
AreaForestAcres
Bucks LakePlumas National Forest680
Chips CreekPlumas National Forest12,940
Devils RockShasta-Trinity National Forest16,209
Kettle Mtn.Shasta-Trinity National Forest4,589
Lake EleanorShasta-Trinity National Forest397
Middle ForkPlumas National Forest29,278
North Fork Middle Fork American RiverTahoe National Forest11,245
West GirardShasta-Trinity National Forest37,516
References (11)
  1. Brouillet, L. 2008. The taxonomy of North American loti (Fabaceae: Loteae): New names in Acmispon and Hosackia. Journal of the Botanical Research Institute of Texas 2:387-394.
  2. Flora of North America Editorial Committee (FNA). 2023. Flora of North America north of Mexico. Vol. 11. Magnoliophyta: Fabaceae, parts 1+2. Oxford Univ. Press, New York. xxvii + 1108 pp.
  3. Global Biodiversity Information Facility (GBIF). 2026. Global Biodiversity Information Facility (GBIF) data portal. Online. Available: https://www.gbif.org/ (accessed 2026).
  4. iNaturalist. 2026. Online. Available: https://www.inaturalist.org (accessed 2026).
  5. Jepson Flora Project (eds.) 2026. Jepson eFlora. Online. Available: https://ucjeps.berkeley.edu/eflora/ (accessed 2026).
  6. 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.
  7. Meyers, S.C., T. Jaster, K.E. Mitchell, T. Harvey, and L.K. Hardison, editors. 2020. Flora of Oregon. Volume 2: Dicots A-F. Botanical Research Institute of Texas, Fort Worth, TX. 861 pp.
  8. NatureServe. 2026. NatureServe Network Biodiversity Location Data. NatureServe, Arlington, Virginia.
  9. Oregon State University (OSU). 2026. Oregon Flora website. Oregon State University Herbarium at Oregon State University. Online. Available: https://oregonflora.org/ (accessed 2026).
  10. <p>NatureServe's Rapid Analysis of Rarity and Endangerment Conservation Assessment Tool (RARECAT). 2025. Version: 2.1.1 (released April 04, 2025).</p>
  11. Southwest Environmental Information Network (SEINet). 2026. Collections Databases. Online. Available: https://swbiodiversity.org/seinet/collections/index.php (accessed 2026).