This site and its content are under development.

Blechnum spicant (L.) Roth, Hard-fern

Account Summary

Native, common, widespread and locally abundant. European temperate and widely disjunct circumpolar.

1860; Smith, Rev Prof R.W.; Co Fermanagh.

Throughout the year.

Growth form and preferred habitats

A very characteristic, easily recognised wintergreen, rosette-forming, heterophyllous, strongly calcifuge fern of wet, acidic, generally peaty conditions in a wide variety of habitats, B. spicant is especially common in damp woodlands, both deciduous and coniferous. The species is also commonly found on more open upland heathy moorland and montane blanket bog, especially along stream and ditch banks in such sites. Hultén (1962) comments that, "in most parts of its area [ie he is referring here to its whole range], it is a calcifuge, but this is not always so in Scandinavia." Jonsell et al. (2000) instead regard it as a plant of, "mostly oligotrophic ground [ie nutrient-poor, unproductive]; apparently indifferent to lime."

Ecology

Hard-fern does not tolerate drought, but rather it requires permanently damp, humid, yet relatively freely drained, sheltered and usually somewhat shaded conditions for optimum growth and competitive ability (Page 1997). Frequently it becomes locally dominant, forming extensive patches of overlapping rosettes in damp hollows in woodland, or along steep, damp, acid riverbanks, where the depth of shade varies from light to moderate. Apart from woods, cliffs, stream and roadside banks and old, acidic-rock quarries, the fern is much sparser or absent in lowland habitats, particularly in the areas of better agricultural soils.

Hard-fern is well named, the fronds being rather leathery, not to say rigid, so that they appear unattractive to all but extremely hungry grazing animals. Putting this another way, the rosettes are tolerant of moderate but not heavy grazing pressure. Management of upland grazing involving cyclical burning to create a mosaic of young and older vegetation is undoubtedly detrimental to this fern, which can be locally eliminated by such practices. (Sinker et al. 1985; Page 1997).

Reproduction

The plant produces separate, quite dissimilar sterile and fertile fronds: the latter are longer and bear much narrower pinnae that on the underside bear paired linear sori covered by two long indusia either side of the midrib.

Fermanagh occurrence

B. spicant occurs on moors and upland bogs in sheltered spots right up to near the highest levels on mountains in Fermanagh. Very dwarf specimens of Hard-fern grow in sheltered damp hollows, along peat banks and between rocks close to the summit of Cuilcagh, the highest mountain. B. spicant finds very many suitable sites in Fermanagh and has been recorded from 366 tetrads, 69.3% of the tetrads in the VC, making it considerably more frequent and widespread than even Pteridium aquilinum (Bracken) (301 tetrads, 57.0%). It is found almost throughout the VC, but avoids lime and base-rich conditions and therefore is absent particularly from some fertile, intensively cultivated lowland areas.

In the very wet oceanic climate of Fermanagh, peat can develop directly over limestone and calcareous sandstone so that B. spicant can occur, but only very locally, in small pockets or on wider stretches of damp, acid, organic soil, even in what appears from the map or general appearance to be geologically unsuitable limestone terrain.

British and Irish occurrence

Hard-fern is very common and widespread throughout most of the British Isles, especially in the wetter N and W areas. It is much less prevalent, or indeed absent, in parts of the east and midlands on both islands. It is most markedly absent on the clay, chalk and limestones of S England. B. spicant has contracted to an unknown extent in the Irish and English Midlands, probably due to a combination of factors causing habitat loss, including woodland clearances, destruction of lowland heathland to create improved pasture, general intensification of farming practices, building development, and industrial and domestic air pollution; it is sensitive to all of these (Jermy et al. 1978; Jermy & Camus 1991; Page 1997).

European occurrence

B. spicant is widespread in W and C Europe, oceanic conditions allowing it to spread northwards up the coast of Norway to within the Arctic Circle. It is also found on the Atlantic islands (Iceland, the Faeroes, Azores, Madeira and the Canaries). Towards the Mediterranean it becomes more dispersed and local, but it is found (however rarely), on the southern tip of the Iberian Peninsula, Corsica, Sardinia, Sicily and Crete. There appears to be considerable doubt about its presence on the Balearic Isles (Tutin et al. 1993) and Jalas & Suominen (1972) do not map it there. In SE Europe, it reaches, but is scarce and local, in Turkey and in Asia Minor (Jalas & Suominen 1972, Map 139; Page 1997).

World occurrence

Beyond Europe, B. spicant has a very widely disjunct discontinuous range in middle temperate latitudes around the northern hemisphere, occurring locally in N Asia, Japan (where a var. nipponicum (Kuntze) Miyabe & Kudo is recognised), Alaska and the Eastern Pacific states of N America (Hultén 1962, Map 143; Hultén & Fries 1986, Map 73). In the opinion of the current author (Ralph Forbes), the distribution is so extremely disjunct it really is stretching the concept to breaking point to refer to it as circumpolar, but in some heavily qualified context it might fit this description.

Names

The genus name 'Blechnum' is derived from a Classical Greek fern name 'blechnon', which in view of the rarity of the modern species of this name in the Mediterranean area, probably was not applied to the same plant at all (Gilbert-Carter 1964; Stearn 1992). The Latin specific epithet 'spicant' means 'tufted' or 'spiked', probably referring to the often shuttlecock manner of growth of the whole plant, or to the relatively rigid, spike-like appearance of the pinnae (Johnson & Smith 1946; Step & Jackson 1945; Gledhill 1985).

Alternative local English common names include 'Deer Fern', 'Foxes Fern', 'Herrin'-bone Fern' or 'Fishbone Fern' (the latter two both being fitting names, especially when applied to the shape of the distinctive fertile frond), 'Rough Spleenwort' and 'Snake Fern' (Britten & Holland 1886; Step & Jackson 1945).

The species is not very variable, but a small number of varieties of the fern, including a crested form, are quite commonly grown in gardens.

Threats

B. spicant is susceptible to the more intensive agricultural practices and associated habitat changes, eg heather burning, bog drainage, removal of hedges and woodland felling. On the other hand, it invades coniferous plantations, where it thrives along the sides of firebreaks and drainage channels. On balance it is holding its own and is much too common to be under any immediate threat. However, changes in the management of upland areas could affect this species either way.