Home/Species/ Desert Yellowhead

Yermo xanthocephalus

Dorn

Desert Yellowhead

G1Critically Imperiled Found in 2 roadless areas NatureServe Explorer →

G1Critically ImperiledGlobal Rank

HighThreat Impact

Identity

Unique IDELEMENT_GLOBAL.2.150568

Element CodePDASTCY010

Record TypeSPECIES

ClassificationSpecies

Classification StatusStandard

Name CategoryVascular Plant

Endemicendemic to a single state or province

KingdomPlantae

PhylumAnthophyta

ClassDicotyledoneae

OrderAsterales

FamilyAsteraceae

GenusYermo

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

This species, the sole member of the genus Yermo, is unique in the cacalioid group of the aster family (Asteraceae or Compositae) in having yellow involucral bracts and a thick, elongate taproot, and in its distribution in a desert habitat.

Conservation Status

Rank Method Rank calculation - Biotics v2

Review Date2022-08-19

Change Date1992-11-30

Edition Date2022-08-19

Edition AuthorsB. Heidel (2004), rev. Treher (2022)

Threat ImpactHigh

Range Extent<100 square km (less than about 40 square miles)

Number of Occurrences1 - 5

Rank Reasons

Yermo xanthocephalus is a perennial herb representing a monotypic genus that is either recently evolved (although quite disjunct from its nearest relatives) or is relatively ancient and in its last refugium. It is known from two occurrences in central Wyoming in the western United States and both are on lands managed by the Bureau of Land Management. This species is vulnerable to habitat degradation and loss due to it limited population size, number of occurrences and area of occupancy, and range extent. This species is reliant on the continuation of measures to restrict threats of mining, recreation, grazing, and other stressors. One of the two occurrences is not protected from mineral exploration. Based on available data, the species appears to be stable in the short-term with management.

Range Extent Comments

Yermo xanthocephalus occurs in the western United States where it is endemic to to the Beaver Rim area in the Sweetwater River Plateau of Fremont County, Wyoming.

Occurrences Comments

This species is known from two locations, one in the Cedar Rim area and one in the Sand Draw area of Fremont County, Wyoming.

Threat Impact Comments

The main threat to this species is mineral extraction and exploration. The township in which it occurs was publicized in state newspapers as the center of a new boom in opal exploration, March 2005, though the exploration activity is concentrated 2+ miles to north. One occurrence is protected from surface entry and mining through 2028 but the Cedar Rim occurrence is not protected by a mineral withdrawal, as of 2021 (USFWS 2021). Although not currently threats, invasive species, wildfire, and drought could be an issue in the future. Grazing occurs in the vicinity, but has not been observed to be a threat. Without continued management and protection, threats of off road vehicles and mining (at the Sand Draw) could become impactful in the future.

Ecology & Habitat

Habitat

The two known occurrences differ in topography and associated vegetation communities. At the Sand Draw, it grows on sparsely vegetated barren outcrops of white silty clay of the Split Rock Formation in shallow depressions, where snow accumulates contributing to a more moist site than the surroundings. At Cedar Rim, plants grow on gravelly silt loam of a narrow, south-facing band of an escarpment slope of the White River Formation. Here it occurs in the area of transition between cushion plant rim and sagebrush grassland (USFWS 2021).

Terrestrial Habitats

Grassland/herbaceousDesertBarrensBare rock/talus/scree

Other Nations (1)

United StatesN1

Province	Rank	Native
Wyoming	S1	Yes

Threat Assessments

Threat	Scope	Severity	Timing
3 - Energy production & mining	Large (31-70%)	Extreme - serious	High (continuing)
3.2 - Mining & quarrying	Large (31-70%)	Extreme - serious	High (continuing)
6 - Human intrusions & disturbance	Pervasive (71-100%)	Serious or 31-70% pop. decline	Insignificant/negligible or past
6.1 - Recreational activities	Pervasive (71-100%)	Serious or 31-70% pop. decline	Insignificant/negligible or past
7 - Natural system modifications	Unknown	Unknown	Low (long-term)
7.1 - Fire & fire suppression	Unknown	Unknown	Low (long-term)
7.1.1 - Increase in fire frequency/intensity	Unknown	Unknown	Low (long-term)
8 - Invasive & other problematic species, genes & diseases	Unknown	Unknown	Low (long-term)
8.1 - Invasive non-native/alien species/diseases	Unknown	Unknown	Low (long-term)
8.1.1 - Unspecified species	Unknown	Unknown	Low (long-term)
11 - Climate change & severe weather	Pervasive (71-100%)	Unknown	Low (long-term)
11.2 - Droughts	Pervasive (71-100%)	Unknown	Low (long-term)

Plant Characteristics

DurationPERENNIAL, Long-lived

Economic Value (Genus)No

Roadless Areas (2)

Idaho (1)

Area	Forest	Acres
Bear Creek	Caribou-Targhee National Forest	118,582

South Dakota (1)

Area	Forest	Acres
Indian Creek	Buffalo Gap National Grassland	24,666

References (7)

Dorn, R. D. 1991. Yermo xanthocephalus (Asteraceae: Senecioneae) a new genus and species from Wyoming. Madrono 38(3): 198-201.
Dorn, R.D. 1992. Vascular plants of Wyoming, 2nd edition. Mountain West Publishing, Cheyenne, Wyoming.
Fertig, W. 1995c. Status report on Yermo xanthocephalus in central Wyoming. Unpublished report prepared for the Bureau of Land Management, Wyoming State Office and Rawlins District by the Wyoming Natural Diversity Database, Laramie, WY. 46 pp.
Flora of North America Editorial Committee (FNA). 2006b. Flora of North America north of Mexico. Vol. 20. Magnoliophyta: Asteridae, part 7: Asteraceae, part 2. Oxford Univ. Press, New York. xxii + 666 pp.
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.
U.S. Fish and Wildlife Service (USFWS). 1998. Endangered and threatened wildlife and plants: proposed threatened status for the plant Yermo xanthocephalus. Federal Register 63(245):70745-70751.
U.S. Fish and Wildlife Service (USFWS). 2021. Draft Recovery Plan for Desert Yellowhead (Yermo xanthocephalus). U.S. Fish and Wildlife Service, Upper Colorado Basin Region Denver, Colorado.

Yermo xanthocephalus

Habitat

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