Desert Shaggy Mane
Podaxis pistillaris
Photographed in Phoenix, Maricopa Co., Arizona. Nov 12, 2006. The full resolution image is available at Wikimedia.
This is probably the most common mushroom in the Sonoran Desert. It is found in deserts world wide. The fruiting body appears above ground within a few days after a soaking rain during the cooler months. It is fibrous and woody and the cap remains closed down around the gills and spores, presumably to protect them from desiccation.