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Chylismia scapoidea

(Torr. & Gray) Nutt. ex Raim.

Paiute Suncup

G5Secure Found in 3 roadless areas NatureServe Explorer →
G5SecureGlobal Rank
UnknownThreat Impact
Identity
Unique IDELEMENT_GLOBAL.2.1252962
Element CodePDONA031T0
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryVascular Plant
Endemicendemic to a single nation
KingdomPlantae
PhylumAnthophyta
ClassDicotyledoneae
OrderMyrtales
FamilyOnagraceae
GenusChylismia
Other Common Names
Barestem Evening-primrose (EN) Naked-stemmed Evening-primrose (EN)
Concept Reference
Flora of North America Editorial Committee (FNA). 2021. Flora of North America north of Mexico. Vol. 10. Magnoliophyta: Proteaceae to Elaeagnaceae. Oxford Univ. Press, New York. xxiv + 456 pp.
Taxonomic Comments
FNA (2021, vol. 10) includes Camissonia bairdii in Chylismia scapoidea ssp. macrocarpa. This record is for that broad treatment of Chylismia scapoidea. Welsh et al. (2015) treats it as distinct.
Conservation Status
Rank Method Rank calculation - Biotics v2
Review Date2026-02-11
Change Date1988-08-01
Edition Date2026-02-11
Edition AuthorsSoteropoulos (2026)
Threat ImpactUnknown
Range Extent200,000-2,500,000 square km (about 80,000-1,000,000 square miles)
Number of Occurrences> 300
Rank Reasons
Chylismia scapoidea is a wide-ranging annual herb found in dry, open sites on clay, sandy, or gravelly soils, slopes or flats, mixed salt and cool desert shrublands, blackbrush, and pinyon-juniper woodland. It occurs in the western United States from eastern Oregon to western Montana south through western and central Wyoming to northwestern New Mexico and northern Arizona. There are likely over 300 occurrences, which face threats from recreational activities (especially off-road vehicles), altered fire regime, invasive species, herbivory, and drought. Little is known about trends, but with a large range extent and large number of occurrences, abundant habitat, and broad habitat preferences, this species is considered secure.
Range Extent Comments
Chylismia scapoidea occurs in the western United States from eastern Oregon to western Montana south through western and central Wyoming to northwestern New Mexico and northern Arizona (FNA 2021). Range extent was estimated to be over 950,000 square kilometers using herbarium specimens and photo-based observations documented between 1994 and 2025 (RARECAT 2025, GBIF 2026, iNaturalist 2026, SEINet 2026).
Occurrences Comments
By applying a 1 km separation distance to herbarium specimens and photo-based observations documented between 1994 and 2025, it is estimated that there are over 225, and likely over 300, occurrences rangewide (RARECAT 2025, GBIF 2026, iNaturalist 2026, SEINet 2026).
Threat Impact Comments
Although threats are not widely documented, this species is threatened by recreational activities (especially off-road vehicles), altered fire regime, invasive species, herbivory, and drought, though there is insufficient data, including anecdotal accounts, to understand scope and severity of threats for this species (UNHP 2023, SEINet 2026).
Ecology & Habitat

Habitat

Chylismia scapoidea grows in dry, open sites on clay, sandy, or gravelly soils, slopes or flats, mixed salt and cool desert shrublands, blackbrush, and pinyon-juniper woodland (Heil et al. 2013, Welsh et al. 2015, FNA 2021).
Terrestrial Habitats
Woodland - ConiferShrubland/chaparralBarrens
Other Nations (1)
United StatesN5
ProvinceRankNative
ColoradoS3Yes
MontanaSNRYes
WyomingS4Yes
UtahSNRYes
WashingtonSNRYes
New MexicoS4Yes
NevadaSNRYes
ArizonaSNRYes
IdahoSNRYes
OregonSNRYes
Threat Assessments
ThreatScopeSeverityTiming
6 - Human intrusions & disturbanceUnknownUnknownHigh (continuing)
6.1 - Recreational activitiesUnknownUnknownHigh (continuing)
7 - Natural system modificationsUnknownUnknownHigh (continuing)
7.1 - Fire & fire suppressionUnknownUnknownHigh (continuing)
7.1.1 - Increase in fire frequency/intensityUnknownUnknownHigh (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)
8.2.2 - Named speciesUnknownUnknownHigh (continuing)
11 - Climate change & severe weatherUnknownUnknownHigh (continuing)
11.2 - DroughtsUnknownUnknownHigh (continuing)

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Plant Characteristics
DurationANNUAL
Economic Value (Genus)No
Roadless Areas (3)
Utah (1)
AreaForestAcres
0419020Ashley National Forest355,684
Wyoming (2)
AreaForestAcres
0401019Ashley National Forest6,202
Horse Creek MesaBighorn National Forest77,808
References (9)
  1. Flora of North America Editorial Committee (FNA). 2021. Flora of North America north of Mexico. Vol. 10. Magnoliophyta: Proteaceae to Elaeagnaceae. Oxford Univ. Press, New York. xxiv + 456 pp.
  2. Global Biodiversity Information Facility (GBIF). 2026. Global Biodiversity Information Facility (GBIF) data portal. Online. Available: https://www.gbif.org/ (accessed 2026).
  3. Heil, K.D, S.L. O'Kane Jr., L.M. Reeves, and A. Clifford. 2013. Flora of the Four Corners Region. Vascular Plants of the San Juan River Drainage: Arizona, Colorado, New Mexico, and Utah. Monographs in systematic botany from the Missouri Botanical Garden, Vol. 124, Missouri Botanical Garden Press, St. Louis, MO. xvi + 1098 pp.
  4. iNaturalist. 2026. Online. Available: https://www.inaturalist.org (accessed 2026).
  5. <p>NatureServe's Rapid Analysis of Rarity and Endangerment Conservation Assessment Tool (RARECAT). 2025. Version: 2.1.1 (released April 04, 2025).</p>
  6. Southwest Environmental Information Network (SEINet). 2026. Collections Databases. Online. Available: https://swbiodiversity.org/seinet/collections/index.php (accessed 2026).
  7. Utah Natural Heritage Program (UNHP). 2023. Element Subnational Ranking Form: <i>Chylismia scapoidea</i> ssp. <i>macrocarpa</i> in Biotics 5 database. NatureServe, Arlington, Virginia (accessed 11 February 2026).
  8. Wagner, W.L., and P.C. Hoch. 2009. Nomenclatural corrections in Onagraceae. Novon 19(1): 130-132.
  9. Welsh, S.L., N.D. Atwood, S. Goodrich, and L.C. Higgins. (Eds). 2015. A Utah flora, fifth edition, revised 2015. Monte L. Bean Life Science Museum, Provo, Utah. 987 pp.