A fern of rock crevices, shady ravines, cave entrances and also under overhangs. It prefers moderately base-rich rocks. 0-380 m (above Loch Tay, Mid Perth).
This species was originally described from the coast south of Aberdeen in 1848. It has recently been found in a few inland sites, and may be overlooked elsewhere. However, its taxonomic status `remains uncertain and controversial` (Dyer et al., 2000) and recent allozyme studies do not support its recognition as a species distinct from C. fragilis.
As the characters which define C. dickieana are unresolved, it is impossible to summarise its world distribution.
Count of 10km squares in Great Britain: 5
Count of 10km squares in Ireland: 0
Count of 10km squares in the Channel Isles: 0
RDB Species Accounts
Cystopteris dickieana R. Sim (Woodsiaceae)
Dickie's bladder-fern, Frith-raineach Dhicianach
Status in Britain: VULNERABLE. WCA Schedule 8.
Status in Europe: Not threatened.
C. dickieana was, until recently, thought to be confined to sea caves and adjacent cliffs in Kincardineshire. The population in the cave that has become the locus classicus contains over 200 plants and spores germinate around parent plants on a shallow matrix of sand grains and decayed filamentous algae overlying the gneiss rock. Associated species are Asplenium marinum, Athyrium filix-femina, Dryopteris dilatata and a few species of bryophytes. At least three other populations exist along this coast, where igneous rocks are interlain with garnet/mica-schist which weather to form a reddish, moderately calcareous soil, supporting such species as Astragalus danicus, Geranium sanguineum, Helianthemum nummularium and Koeleria macrantha (Marren 1984).
Herbarium specimens of C. dickieana from a few other localities have recently been detected during searches of British herbaria. However, in 1993 an extant population of considerable extent was located in central Perthshire. The site there is in a ravine on rocks associated with the Loch Tay limestones. Another site was subsequently found in Easterness, and an account of the plant in Britain is given in Tennant (1996). The populations on the cliffs in Kincardineshire are vulnerable to erosion and illegal tipping of domestic refuse, but neither of the inland sites is threatened.
C. dickieana is a pan-boreal species throughout Eurasia and in North America. Its exact status within the C. fragilis complex is still unclear, as are the cytogenetics of the bladder ferns generally. At least three diploid ancestors are known to have been involved in the evolution of the complex. Kincardineshire material of C. dickieana is known to be tetraploid; in continental Europe both tetraploid and hexaploid plants occur.
The rugose spore character has been treated as diagnostic for the species, but recent isoenzyme studies suggest that it has little genetic, and therefore taxonomic, value. However, the genetic make-up of the British populations may provide a clue to the evolution of this group as a whole and the species as we presently conceive it should certainly be conserved pending further work.
A. C. Jermy
PLANTATT - Attributes of British and Irish plants. (.zip 1455KB) This dataset was compiled and published in 2004, and last updated in November 2008. Download includes an Excel spreadsheet of the attributes, and a PDF explaining the background and nomenclature. Note that the PDF version is the booklet as published, whereas the Excel spreadsheet incorporates subsequent corrections. A hardcopy can be purchased from the Centre for Ecology and Hydrology.
Atlas text references
1986. Atlas of north European vascular plants north of the Tropic of Cancer. 3 vols.
Jalas & Suominen (1972)
1978. Ferns and their allies. The Island of Mull: a survey of its flora and environment. :12.1-12.7.
1983. The history of Dickie’s fern in Kincardineshire. Transactions of the Botanical Society of Edinburgh. 44:157-164.
1997. The ferns of Britain and Ireland, edn 2.
2000. Allozyme, spore and frond variation in some Scottish populations of the ferns Cystopteris dickieana and Cystopteris fragilis. Edinburgh. Journal of Botany. 57:83-105.
1996. Cystopteris dickieana R. Sim in the central and eastern Scottish Highlands. Watsonia. 21:135-139.
1999. British Red Data Books. 1. Vascular plants, edn 3.