Lander, WY – The opal discovery in central Wyoming has prompted the Bureau of Land Management to make 360 acres off-limits to vehicles. The idea is to protect the Desert Yellowhead, a foot-tall, sunflower-like plant that's listed as threatened under the Endangered Species Act. The closure comes about three weeks after the Wyoming Geological Survey announced the discovery of opal in the area. The closed area does not include the opal deposits. But the BLM says the closure will remain in effect until the plant is no longer at risk from vehicles.