Desert yellowhead (Yermo xanthocephalus).

On March 14, we listed the desert yellowhead, a perennial herb in the sunflower family, as a threatened species. The only known population, which included approximately 12,000 plants according to surveys conducted in 2001, exists on less than 50 acres (20 ha) of public property administered by the Bureau of Land Management (BLM) in southern Fremont Country, Wyoming. Its restricted range and small population size make this plant vulnerable to extinction by natural and human-caused disturbance and environmental stress. Potential oil and gas field development on a 1,160-acre (470-ha) lease that includes the plant's habitat is one threat to the species. Two large leases for oil and gas development were issued in 1996 and 1997 that could impact the plant and its habitat, with no specific stipulations included to protect the plant. The Service is working with the BLM to develop a conservation agreement.