A deciduous fern found growing in open wet woodland and around rock outcrops at low altitudes, and in damp, sheltered hollows of upland boulder scree. Its substrates are usually mildly acidic, but it can grow in scree derived from quite base-rich mica-schists. 0-945 m (Stob Binnein, W. Perth).
D. expansa was first mapped by Jermy et al. (1978). Some lowland sites have been lost to woodland clearance, but upland sites are relatively stable. The species is, however, difficult to identify and is almost certainly under-recorded.
Circumpolar Boreal-montane element, with a disjunct distribution.
There are no images in this gallery.