1. ECOS
2. Species Profile for Desert yellowhead (Yermo xanthocephalus)

Desert yellowhead (Yermo xanthocephalus)

Listing Status:   

Where Listed: WHEREVER FOUND

General Information

Desert yellowhead is a tap-rooted perennial herb. The entire plant is smooth, possessing no hair or other projections. The stems have leathery leaves and grow up to 30 centimeters (cm) (11.8 inches (in.)) tall. The leaves grow in an alternating pattern and are often folded along the vein in the middle of the leaf. Flower heads are numerous (25 to 180) and crowded on top of the stem. Each flower head contains four to six yellow disk flowers (ray flowers are absent) surrounded by four to six yellow, keeled involucral bracts (modified leaves below the flower head). The seeds have tufts of white hairs (Dorn 1991, Heidel 2002, and Heidel et al. 2008) For more information and reference list, please select the 5-year review link below.

• States/US Territories in which the Desert yellowhead, Wherever found is known to or is believed to occur:  Wyoming
• US Counties in which the Desert yellowhead, Wherever found is known to or is believed to occur:  View All
• Additional species information

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No conservation plans have been created for Desert yellowhead.

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» Life History

Habitat Requirements

Desert yellowhead plants in the Sand Draw population are almost exclusively found on poorly developed soils and only occasionally on more well-developed soils (Scott and Scott 2009). Where they are found on well-developed soils, they occur a meter or less from the soils without a well-developed soil profile. Soils within the Sand Draw population had a higher silt content, were slightly more alkaline, slightly lighter in color, had lower loss on ignition organic matter, and had lower water retaining capacity than soils outside of the population (Scott and Scott 2009; Heidel et al. 2011). The soils within the Sand Draw population are distinct from those of the surrounding steppe by at least 8 of the 17 soil properties that were tested (Heidel et al. 2011). These results supported the hypothesis that desert yellowhead is a habitat specialist and is limited in distribution by soil characteristics. In 2010, additional soil sampling was conducted. This additional sampling supported the original hypothesis that the soils of the Sand Draw population of desert yellowhead differs from the soils of the surrounding sagebrush steppe. However, 10 of the 17 soil properties tested showed differences between the soils of the Sand Draw population and the soils of the Cedar Rim population. In all tests except available phosphorus, the soils of the Sand Draw population differed more from the soils of the Cedar Rim population than they did from one or both of the surrounding steppe soils and the potential site soils (Heidel et al. 2011). Only one soil variable, the soluble sodium level, was found to be similar between the two populations of desert yellowhead. These results do not support the hypothesis that desert yellowhead is a habitat specialist that is limited in distribution by soil characteristics. For more information and reference list, please select the 5-year review link above.

Movement / Home Range

The occupied habitat of the Sand Draw population of desert yellowhead is restricted to shallow depressions created by erosion in outcrops of Miocene sandstones and limestones of the Split Rock Formation at its junction with the White River Formation (Van Houten 1964; Love 1961). These depressions accumulate drifting snow and may be more moist than surrounding areas. The vegetation of these sites is typically sparse, less than 10 percent, and consists primarily of low cushion plants and scattered clumps of Oryzopsis hymenoides (Indian ricegrass) (Fertig 1995; Heidel et al. 2011). Additionally, there is an abrupt border between the occupied habitat of the Sand Draw population and the surrounding sagebrush steppe (Heidel et al. 2011). Conversely, the Cedar Rim population does not occur on an outwash; the seven subpopulations occupy a narrow band along escarpment slopes (Heidel et al. 2011). These slopes are generally south-facing, mostly at the intersection between the cushion plant rim and sagebrush grassland toeslope communities on gravelly silt loam derived from the White River Formation (Heidel and Handley 2010, as cited in Heidel et al. 2011). Vegetation cover consists of 5 to 20 percent bunchgrasses, including Pseudoroegneria spicata (bluebunch wheatgrass) and Koeleria cristata (junegrass), accompanied by diverse forbs (broad-leaved herbs). Therefore, the habitats of the two populations differ not only in their topographic positions (mid-slope vs. base), but also in vegetation structures (bunchgrass community vs. barren cushion plant community) (Heidel et al. 2011). For more information and reference list, please select the 5-year review link above.

Reproductive Strategy

Desert yellowhead is a long-lived perennial that produces sexually by seed and asexually by vegetative buds (Scott and Scott 2009). At least some desert yellowhead plants have a lifespan of a minimum of 21 years (Scott and Scott 2009). This species is typically described as a classic ‘K’ selected species, characterized by a long-lived perennial growth form, adaptation to severe habitats, and low annual reproductive output (Fertig 1995). Desert yellowhead usually flowers from mid-June to August and may prolong flowering, or flower for a second time in September (Heidel 2002). The growing season has an average of 124 days (Scott and Scott 2009). This species is likely pollinated by visually-oriented insects attracted to its bright disk flowers and bracts (Dorn 1991). Ants and nectar-feeding butterflies were noted as frequent visitors to desert yellowhead flowers (Heidel et al. 2011). The butterfly was identified as the small wood nymph (Cercyonis oetus), a common species in Wyoming that typically feeds on the nectar of yellow composite flowers. Additionally, small skipper butterflies (Hesperiidae family) visit desert yellowhead; however, these butterflies were not identified to species (Scott and Scott 2009). For more information and reference list, please select the 5-year review link above.

» Other Resources

NatureServe Explorer Species Reports -- NatureServe Explorer is a source for authoritative conservation information on more than 50,000 plants, animals and ecological communtities of the U.S and Canada. NatureServe Explorer provides in-depth information on rare and endangered species, but includes common plants and animals too. NatureServe Explorer is a product of NatureServe in collaboration with the Natural Heritage Network.

ITIS Reports -- ITIS (the Integrated Taxonomic Information System) is a source for authoritative taxonomic information on plants, animals, fungi, and microbes of North America and the world.

FWS Digital Media Library -- The U.S. Fish and Wildlife Service's National Digital Library is a searchable collection of selected images, historical artifacts, audio clips, publications, and video.