There is some debate over the hybridity of this cultivar (or cultivar group potentially) and we are pulled in differing directions by the prevalence of hybrid suspicions normally winning out and the relative rarity of true hybridization in most ferns. Regardless of whether it is a mutt or a purebred it is a fine variation on an already classic theme. Finely cut fronds with such regularity in shape that one could easily be forgiven for assuming it to be an unfamiliar species. Cultivar ferns can be a bit marmite but I think even the purists would find this acceptable if not outright agreeable. (It is entirely possible if not likely that the correct name for this plant is 'Cornubiense Foliosum', see Martin Rickard's book on Polypodium for a full idea of the complexities)
