Cryptogramma crispa (L.) R. Br. ex Hook., Parsley Fern
Account Summary
Native, extinct. European boreal-montane.
1866; McDonald, J.; Altscraghy, Cuilcagh slopes.
Growth form and preferred habitats
This small, clump-forming, deciduous, polymorphic, montane fern with its distinctive, finely cut sterile fronds and separate, narrower fertile branches is very much rarer in Ireland than in Britain. In both islands, it is strictly confined to calcium-free, silica-rich, acid soils. The species is so sensitive to bases that it is absent from otherwise suitable geological areas, if such habitats are subject to any enrichment with base-rich cations, for instance from salt-laden onshore winds (Jermy et al. 1978).
C. crispa prefers well-drained sites on steep, but relatively stable, screes, but it also occupies crevices on cliff ledges. In some areas it can be found on artificial habitats, namely mortar-free dry stone walls (Page 1997; T.D. Dines, in: Preston et al. 2002).
Fermanagh occurrence
The solitary mid-19th century Fermanagh record of John McDonald (of whom we know absolutely nothing at present), from "the East side of Caulteach (Cuilcagh) Mountain, near Florencecourt; sparingly", is from a very suitable site well furnished with acidic rock cliffs and steep screes (Cybele Hibernica 1866). Regrettably, this appears to have been one of the fleeting, casual occurrences that appear to typify the behaviour of this very strict calcifuge species in Ireland. No one has seen the fern in Fermanagh since, despite diligent searching for it on the appropriate parts of this very remote mountain area.
Interestingly, another fleeting occurrence of the species was recorded in 1937 from adjacent Co Cavan (H30): "a solitary tuft of the plant found growing out of a crack in the overhanging face of a small boulder on the W side of Bruse Hill at about 183 m altitude" (Cole 1938). It was reported as being killed the following year, probably by drought (Praeger 1946; Reilly 2001). On account of wider geographical distribution and biodiversity aims, this fern is included on the NIEA list of Priority Species of special concern requiring conservation action.
Irish occurrence
The presence of C. crispa in Ireland has declined during the 20th century from ten VCs to just three at present. Recent sightings are mentioned in the Irish Red Data Book, from one site in W Galway (H16), three in Down (H38) and two in Co Antrim (H39) (Curtis & McGough 1988). Plants in N Irish sites tend to be small and inconspicuous, growing in rock crevices on cliffs (Hackney et al. 1992). Flora of Connemara and the Burren noted that the fern is, "very rare in Ireland, and in some of its stations little more than a casual" (Webb & Scannell 1983).
British occurrence
In Britain, C. crispa has a strongly marked northern and western distribution, and its headquarters very obviously occurs in the Scottish Highlands. Losses in England occurred in the Southern Pennines prior to 1930, perhaps as a result of fern collecting, but the distribution now appears stable (New Atlas).
European and world occurrence
This variable, polymorphic fern species has several named lower taxa with separate distribution areas. In Europe, it has an Arctic-alpine distribution, the main areas of occurrence being the mountains of W Scandinavia, the British Isles, the Alps and the Pyrenees, with scattered stations south within the Iberian Peninsula, Corsica, N Italy and the Macedonian mountains (Jalas & Suominen 1972, Map 61; Page 1997).
In more continental areas of Europe, C. crispa tends to be found in the upper subalpine to mid-alpine belt in sites with reliable blanketing winter snow-cover (Jonsell et al. 2000). Indeed, while Parsley Fern evades severe frost in this manner, the species also chooses sites that allow it to avoid high summer maximum temperatures. The present-day distribution of C. crispa in Ireland and the Scottish Highlands correlates closely with the 24°C maximum summer temperature summit isotherm (ie for the highest places in the landscape). In the Scottish Lowlands, England and Wales the equivalent temperature limit is the 26°C isotherm (Conolly & Dahl 1970).
Beyond Europe, C. crispa, in the broad sense, extends to Asia Minor and there are at least four geographically differentiated races which carry the plant to the Himalaya, China, Alaska and N America (Hultén 1958; Hultén & Fries 1986, Map 32).
Names
The genus name, 'Cryptogramma', is derived from two Greek words, 'kruptos' = 'hidden', and 'gramme' = 'a line', an allusion to the fact that the lines of the sori are not as evident as on most other fern species, being covered by the rolled frond margin (Step & Jackson 1945; Jonsell et al. 2000). The specific epithet 'crispa', meaning 'curly', or 'with wavy margins', refers to the Parsley-like appearance of the deeply cut sterile fronds (Gilbert-Carter 1964).
The English Common name most commonly used is 'Parsley Fern', which Grigson (1974) reckons dates from the 18th century, the plant resembling curled forms of parsley. Other Common names less often heard include 'Rock Brakes', and 'Curled Brakes'; 'Brakes', 'Brake' or 'Brake-fern' are general names for the larger ferns dating back to Turner, Lyte and Gerard in the mid-16th century (Britten & Holland 1886). 'Stone Fir' and 'Mountain Parsley' are two 19th century 'book names' (ie, a derogatory term for plant names invented by other authors), also listed by Britten & Holland (1886).
Threats
None.