Genus Lagopus is a scientific name that refers to a group of birds commonly known as ptarmigans. They are birds of the grouse family and are found in various parts of the world. There are several synonyms used for this genus, including Lagopus, Lagopus hyperboreus, and Lagopus muta. These synonyms refer to different species and subspecies of ptarmigans. The Lagopus hyperboreus is commonly known as the rock ptarmigan and is found in the high Arctic regions of North America and Europe. The Lagopus muta is commonly known as the willow ptarmigan and is found in the subarctic regions of North America and Eurasia. Knowing these synonyms can be helpful in identifying and studying these fascinating birds.