In optimal conditions the sporophyte can form very extensive clonal patches, the largest in the British Isles covering many square metres and with over a thousand fronds. Most however are much smaller and by virtue of their exacting ecology restricted to very small features where they may remain at a very constant size and frond number over decades, or even centuries.
Individual fronds may remain alive and functional over 5 or more years, with their skeletal vascular remains persisting even longer. They are thus prone to being colonised while still alive by a range of small mosses and liverworts which are equally restricted to the very humid habitats in which the fern grows. Very few other species in the European flora support such a range of epiphylls. The rhizome can grow up to 20cm or more in a year but usually much less.
The gametophyte generally occurs as small woolly tufts less than a centimetre deep but in stable, sheltered environments on porous acid substrates it can grow to cover many square metres. It grows very slowly indeed, with sometimes only 1 cell division at the extending tips per week.
Learn about the appearance and functions of the Killarney fern in relation to its environment.
Find out about the reproductive and dispersal patterns of Vandenboschia speciosa.
The lifecycle of the Killarney fern differs depending on the location and conditions in which it grows. Find out more about the differing lifecycles of this fern.