Neornithes Gadow, 1893 - living birds
   Neognathae Pycraft 1900 see Cohort Neognathae Pycraft, 1900
     Galloanserae Sibley, Ahlquist & Monroe Jr., 1988 see Subcohort Galloanserae Sibley, Ahlquist & Monroe Jr., 1988
       [Order] Galliformes Temminck, 1820 - fowl
         phasianoids see Superfamily Phasianoidea Vigors, 1825
           Family Phasianidae Vigors, 1825 - turkeys, grouse, pheasants, partridges
             Subfamily Tetraoninae Vigors - grouse see Family Tetraonidae Vigors, 1825
               Genus Lagopus Brisson, 1760 - ptarmigan
                 Lagopus lagopus (Linnaeus, 1758) - willow grouse
                   01 Lagopus lagopus scotica (Latham, 1787)
                   02 Lagopus lagopus variegata Salomonsen, 1936
                   03 Lagopus lagopus lagopusᵀ (Linnaeus, 1758) - willow ptarmigan
                   04 Lagopus lagopus rossica Serebrovsky, 1926
                   05 Lagopus lagopus koreni Thayer & Bangs, 1914
                   06 Lagopus lagopus maior Lorenz, 1904
                   07 Lagopus lagopus brevirostris Hesse, 1912
                   08 Lagopus lagopus kozlowae Portenko, 1931
                   09 Lagopus lagopus sserebrowskii Domaniewski, 1933
                   10 Lagopus lagopus okadai Momiyama, 1928
                   11 Lagopus lagopus alascensis Swarth, 1926
                   12 Lagopus lagopus muriei Gabrielson & Lincoln, 1949
                   13 Lagopus lagopus alexandrae Grinnell, 1909
                   14 Lagopus lagopus leucoptera Taverner, 1932
                   15 Lagopus lagopus alba (Gmelin, 1789)
                   16 Lagopus lagopus ungavus Riley, 1911
                   17 Lagopus lagopus alleni Stejneger, 1884