Because no diploid ancestors have been found, Polystichum braunii is thought to be an ancient tetraploid. Its sterile hybrid with P . acrostichoides , P . × potteri , is discussed under P . acrostichoides . Polystichum braunii × lonchitis has been reported from southeast Alaska (S. L. Welsh 1974). This hybrid has been cytologically confirmed in Europe and named P . × meyeri Sleep & Reichstein (A. Sleep and T. Reichstein 1967). It has narrower and less divided leaves than P . braunii and poorly developed auricles. Polystichum braunii × lonchitis was described by J. Ewan (1944), but the type (from British Columbia) is P . braunii × munitum (A. Sleep and T. Reichstein 1967). This latter hybrid is the postulated progenitor of P . setigerum (D. H. Wagner 1979). North American P . braunii has been segregated as var. purshii Fernald, distinguished from European populations (var. braunii ) by having broader microscales.