I don't think is is A. muscaria given the very yellow tinge to the stalk...
Medium size mushroom, red speckled cap, white stem, suspect a type of amanita unsure which.
Agaricus sp. Rock Creek Park, Washington, DC, USA
"I survived the Destroying Angel" article: https://blog.mycology.cornell.edu/2006/11/22/i-survived-the-destroying-angel/
More on this fungus: http://blog.mycology.cornell.edu/2006/11/28/the-destroying-angel/
The Amanitaceae are a family of fungi or mushrooms. The family, also commonly called the amanita family, is in order Agaricales, gilled mushrooms. The family consists primarily of the genus Amanita, but also includes the genera Catatrama and Limacella.