Spotted at the Bangor Garden Show was Polypodium attenuatum ‘Falax’ or something like that. It was labeled Fern ‘Falax’ and a search got us the Latin name. But there the trail gets a little overgrown, with only one site – in Hawaii – calling it the like. It may be a bit rare in the world, given the lack of sites mentioning it at all, let alone in detail. But here you go, from the Kauai Nursery: “An interesting fern with highly divided green fronds. Needs lots of water, do not let this fern dry out between waterings. Grow in a pot, makes a good indoor fern. Plant outdoors in a boggy area or in a water garden.” That last bit does not apply to Maine since it looks like the plant is Zone 9 or so.