Dryopteris filix-mas (L.) Schott, Male-fern

Account Summary

Growth form and preferred habitats

Male-ferns in Britain and Ireland were originally conceived to be a single species and the history of the subsequent splits and their naming is a complicated one. In Fermanagh, we have records for a total of five species of Dryopteris plus two hybrids. Among the male-ferns, we recognise and distinguish D. filix-mas and D. affinis (Scaly Male-fern), the latter an apomictic species, several forms of which have in the past been considered and recorded as separate species. D. filix-mas is a large, common deciduous fern that is distinguished from D. affinis by the lack of a black mark at the point where the pinna midribs meet the rachis, and by its sparser, paler, straw-coloured scales on the stipe.

D. filix-mas is a large, vigorous, shuttlecock-forming perennial, the vertical rhizome of which is long-lived and can become quite massive. It is common in woods, hedgerows, streamside banks, ditches, roadside verges, rocky slopes, screes and cliff ledges. The species has an unusually wide tolerance of soil pH (from pH 3-8), nutrient status and water supply, which is reflected in the huge variety of habitats it occupies. Experimental measurements made in W Europe to determine the role of root cation-exchange properties of fern species found that D. filix-mas was indifferent to both soil pH and calcium carbonate content (Koedam et al. 1992).

D. filix-mas performs best in lowland sites with relatively fertile soil and little disturbance. On well-drained slopes, within mixed deciduous woodland, it can dominate stretches of the floor vegetation. Often in this type of seasonally shaded habitat, its main competitors are other large ferns. Most frequently these are D. dilatata (Broad Buckler-fern) and Athyrium filix-femina (Lady-fern), but sometimes it also overlaps with the closely related D. affinis.

Unusually for a fern, D. filix-mas is very tolerant of atmospheric pollution and it colonises shady, damp, urban areas and industrial sites including rubbish dumps, old brickwork and other less salubrious situations. It is probably true to say that its occurrence is limited only by extremes of exposure, wetness (ie permanent water-logging) and shade, and by heavy disturbance including grazing pressure.

Fermanagh occurrence

This species and D. dilatata (Broad Buckler-fern) are the two most common ferns in Fermanagh, the latter perhaps being slightly more widespread. The Fermanagh Flora Database contains records of D. filix-mas from 462 tetrads, 87.5% of those in the VC, and it is clearly widespread and abundant almost everywhere except in aquatic, heavily disturbed, or very exposed situations. It dominates stretches of the woodland floor at the base of the cliffs of Poulaphouca, on Bilberry Island on Lower Lough Erne, and in parts of the Cladagh River Glen.

Phenology

Fresh annual fronds of D. filix-mas unfurl from early May and are fully expanded by the end of that month. D. filix-mas is one of the hardiest ferns in the British Isles and its fronds are wintergreen to semi-persistent in Fermanagh, depending on degree of exposure, although in truth under our dull, grey skies they probably are semi-senescent for much of the winter (Grime et al. 1988). By late February or earlier, the old fronds are often broken down and they are certainly dying off, soon to be replaced by the growth of fresh new croziers on the upright rhizome.

Reproduction

Male-fern plants produce colossal amounts of spores which are released from August to November (Page 1997). Despite this fecundity, it is not at all clear with what degree of success it achieves establishment of the sporophyte generation. That this does happen is attested by the presence of young, small, sporophyte plants embedded in cushions of moss on little rises on the floor of woodlands, and occasional plants developing in crevices at various heights on walls (Willmot 1985). A preliminary population study in Derbyshire woodland suggested that recruitment of small D. filix-mas plants was a relatively rare event when compared with D. dilatata, but that once plants of the former established, they might live for a long time (Willmot 1985). A study in Russian woods suggested that plants mature and spore only when over six years of age, and they may survive for 30 to 40 years or longer (Pogorelova & Rabotnov 1978).

On walls, observation indicates that small plants frequently persist for many years, but they seldom achieve maturity and sporing ability. Possibly reasons for such failure are excessive dryness, lack of nutrients, or perhaps because of eventual, inevitable disturbance (Grime et al. 1988).

British and Irish occurrence

D. filix-mas is extremely common throughout the whole of the British Isles, and in fact in terms of spread it is second only to Pteridium aquilinum (Bracken) in the number of hectads in which it occurs (Jermy et al. 1978; New Atlas). Page (1982, 1997) suggests that the presence of Male-fern in Britain and Ireland has diminished in the last two thousand years with the gradual removal of much of the forest vegetation, the natural habitat of the species. Considering just how common and widespread a plant it remains, and its almost unrivalled ability to colonise artificial, man-made habitats, it is hard to see that there is any cause for concern about the species yet, since it clearly manages extremely well in the substitute habitats it now so fully occupies!

European and world occurrence

In Europe, Male-fern is widespread at middle and northern latitudes, thinning northwards but reaching the Arctic circle in Scandinavia, and while present in Iceland it is absent further north in Svalbard (Spitsbergen, Bear Island and Jan Mayen) (Tutin et al. 1993). The distribution also thins towards the south in the Iberian Peninsula, and Male-fern is absent from the Azores, Madeira and the Canaries. Of the Mediterranean islands, it is present only on Corsica and Sicily (Jalas & Suominen 1972, Map 123).

On the world scale, taking D. filix-mas in a broad sense (and recognising that the taxonomic and nomenclature confusion that exists within this group of ferns creates problems when it comes to estimating distribution), beyond its main European base it displays a disjunct circumpolar distribution. In the past, several forms were given separate taxonomic recognition, especially in the far east of Asia, S Africa, S America and a number of island groups in the southern hemisphere, including Madagascar, Hawaii, the Falklands and the Galapagos (Hultén 1962, Map 110; Hultén & Fries 1986, Map 64).

Names

The genus name 'Dryopteris' was first given by the Greek physician, Pedanius Dioscorides (c. 40-90 AD), to a fern growing on oak trees, and is a compound of the Greek 'dryas' = 'oak', and 'pteris' = 'fern' (Gilbert-Carter 1964). The specific epithet 'filix-mas' was first given by the German botanist, Leonhart Fuchs (1501-66), and is derived from Latin 'filix' = 'fern', and 'mas' = 'male', from the supposedly big, bold 'masculine' appearance of the species in comparison with the much more delicate, finely divided fronds of the 'Lady-fern' (Gilbert-Carter 1964).

Uses

The above mention of these ancient and medieval herbalists gives an indication of the fact that Male-fern has a very long history of medicinal use. An oil extracted from the rhizome was used from ancient times as a vermifuge (ie used to kill and expel flatworms, tapeworms and liverfluke). It has also been applied for worming in veterinary medicine (Vickery 1995), although the rhizome also contains a dangerous toxin, thiaminase. The latter is known to cause thiamine deficiency in animals such as horses, cattle and pigs which have eaten the fern. When oil of Male-fern was used for worming, a single sufficient dose was reputed to produce a cure at once, but too much of the toxic drug is poisonous and can cause coma and blindness.

D. filix-mas also contains filixic acid (filicin), and the main toxic activity of the species is due to a phloroglucinol derivative of this substance (Cooper & Johnson 1998). As with all herbal lore quoted here, BE WARNED, and do not attempt to administer any such drug without the guidance of a qualified, licensed medical or veterinary practitioner. Another past herbal use for powdered root of Male-fern was for treating rickets in children, and an ointment was also made and used for healing wounds (Grieve 1931).

Male-fern had other uses similar to those of Bracken, the ash of the burnt fern having applications in glass-making and soap. Young croziers were boiled and eaten like Asparagus. In Norway, at times of hardship, it was used to make beer, the dried fronds being said to make an excellent bitter. Fronds infused in hot water have also been regarded in the past as good fodder for sheep and goats (Grieve 1931).

Threats

None.

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