Identity
Unique IDELEMENT_GLOBAL.2.160595
Element CodePDAST4V0Q0
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryVascular Plant
Endemicendemic to a single nation
KingdomPlantae
PhylumAnthophyta
ClassDicotyledoneae
OrderAsterales
FamilyAsteraceae
GenusHeterotheca
Concept ReferenceKartesz, 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 CommentsHeterotheca zionensis Semple was first described in 1987, based on specimens from southwestern Utah (Kartesz 1994). Cronquist (1994) placed H. zionensis in synonymy under H. villosa. Then, Semple (1996) expanded H. zionensis to "a common taxon distributed over parts of several states rather than a rare one confined to the vicinity of Zion National Park in southwestern Utah", including plants occurring widely in Utah, Arizona, and New Mexico and at locations in Colorado and Idaho (where thought to be introduced). Subsequent authors have also considered H. zionensis to be a distinct species, occurring in several states (Allred et al. 2020, Flora of North America Editorial Committee 2006, Nesom 2020, Stone 1998, Welsh et al 2015). A new taxon was described in 2020, Heterotheca utahensis with overlapping range in northern Utah, "but plants of intermediate morphology are not common", some specimens previously annotated as H. zionensis from northern Utah have been annotated to H. utahensis (Nesom 2020).
Conservation Status
Rank Method Rank calculation - Biotics v2
Review Date2023-12-27
Change Date2023-12-27
Edition Date2023-12-27
Edition AuthorsBen Franklin (1995), rev. G. Thunhorst (1998), rev. C. Nordman (2023).
Threat ImpactLow
Range Extent200,000-2,500,000 square km (about 80,000-1,000,000 square miles)
Number of Occurrences81 - 300
Rank ReasonsHeterotheca zionensis occurs in the western United States, only in Utah, western Colorado, northern and eastern Arizona, New Mexico, and southwest Texas. It is estimated that there are between 81 and 300 occurrences, rangewide including on various National Forests, National Monuments, National Parks, and State Parks in Utah, Arizona and New Mexico. Loss of habitat due to residential and commercial development is a threat, especially in areas with rapid economic growth. There is a lack of information about trends.
Range Extent CommentsHeterotheca zionensis occurs in the western United States, only in Utah, western Colorado, northern and eastern Arizona, New Mexico, and west Texas. Range extent was estimated to be 513,000 square kilometers, using herbarium specimens, photo-based observations, and NatureServe Network occurrence data collected between 1992 and 2023 (Allred et al. 2020, Flora of North America Editorial Committee 2006, GBIF 2023, iNaturalist 2023, NatureServe 2023, Nesom 2020, SEINet 2023, Semple 1996, Welsh et al. 2015).
Occurrences CommentsBy applying a 1 km separation distance to herbarium specimens, photo-based observations, and NatureServe Network occurrence data documented between 1992 and 2023, it is estimated that there are between 81 and 300 occurrences of Heterotheca zionensis rangewide (GBIF 2023, iNaturalist 2023, NatureServe 2023, SEINet 2023).
Threat Impact CommentsLoss of habitat due to residential and commercial development is a threat, especially in areas with rapid economic growth.