Harts tongue fernvirus
The host list given is five species of ferns with generic names starting with P including Phyllitis scolopendrium in which the symptoms are mottling of fronds.
Phyllitis (=Asplenium) scolopendrium
Image of plant habit.
Phyllitis scolopendrium (Hart's-tongue Fern)
Image gallery. Also known as Asplenium scolopendrium L.