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Ceterach officinarum Willd., Rustyback

Account Summary

Native, occasional or fairly frequent. Submediterranean-subatlantic.

1844; Cole, Hon J.L.; Florencecourt.

Throughout the year.

Growth form and preferred habitats

This distinctive, definitely calcicole, evergreen perennial typically occurs either in crevices in cliffs and screes of limestone or other basic rocks, or in the artificial habitat of old lime-mortared walls.

The prevailing damp and relatively mild climate of Fermanagh allows the evergreen fronds to grow most of the year round, and since our high precipitation is rather evenly distributed, checks on C. officinarum growth due to summer drought are few and far between. In the rare event of prolonged dry weather, Rustyback may wilt so severely and curl up so that it appears to have suffered terminally. However, the fronds and their thick backing of overlapping scales have amazing powers of recovery, and thus individuals are very persistent. The fronds can even develop a second flush of sporing sori after such an event (Jermy & Camus 1991). While the fern often appears to be rooted in very dry wall or rock crevices, in reality its roots are frequently embedded in cushions of water-retaining moss or in pockets of damp, black humus derived from dead moss.

Fermanagh occurrence

Only on the limestone cliffs and screes near Boho, at Carrickreagh and in disused quarries at Goladoo near Ederny has Rustyback been found on natural rock surfaces in our survey area. Lime-mortared walls are not all that frequent in Fermanagh, so the fern's real local stronghold is the mortar on old bridge parapets. C. officinarum has been recorded in 69 Fermanagh tetrads, 13.1% of those in the VC. More than half the records are from old bridges scattered throughout the survey area. As the tetrad map shows, it is widely spread across the county, but eleven tetrads have only pre-1975 records, suggesting there has been some local decline of this species.

British and Irish occurrence

C. officinarum is widely distributed throughout the whole of Ireland, but is probably most common to the S and W of the island. The latter comment could also be applied to Britain, but here it is even more south westerly, being frequent only in SW England and Wales and Cumbria, scattered in the Pennines and SW Scotland, but very rare north of the Grampian Highlands and scarce east of the Pennines in England (Jermy et al. 1978; Jermy & Camus 1991).

Europoean and world occurrence

Beyond Britain & Ireland, C. officinarum is widely distributed in SW Europe and the Mediterranean basin where it has its main centre of occurrence, but it also extends eastwards to the Crimea, the Caucasus and C Asia. It also stretches southwest to the Cape Verde Islands (Jalas & Suominen 1972, Map 99; Hultén & Fries 1986, Map 47; Page 1997). The species contracted during the last century and became locally extinct in several areas, mainly along the easterly margins of its natural range in Britain, Germany, Holland, Switzerland, and no doubt elsewhere in mainland Europe (Jalas & Suominen 1972).

Names

Conflicting derivations are given for the genus name 'Ceterach' in the literature. Several sources (eg Gledhill 1985) suggest it is an Arabic name for an unspecified fern, while Gilbert-Carter (1964) believes it is derived from a German word meaning 'itchy', referring to the covering of scales which are said to resemble a cutaneous skin eruption! Step & Jackson (1945) refer back to Turner (1548) The names of herbes (which is always a good place to start!). Turner refers under the name 'Asplenum' or 'Asplenium' to the apothecary's 'Citterache'. Step & Jackson (1945) also regard 'Ceterach' (or, alternatively, 'Chetherak'), as possibly being of Arabic origin, apothecaries "using it as a medicine for troubles of the spleen and liver".

The species name 'officinarum' as always is a reference to the apothecary's shop, the 'officina', where medicinal plants were kept, and thus infers that the species was used in medicine (Gilbert-Carter 1964).

In his Herbal of 1568, Turner is quoted as saying that he had heard of no English name of the fern, although the ancient name 'Asplenum' and the French(!) 'Ceterache' were familiar to him. Turner then suggested several English names himself: "It may well be called in English 'Ceterache' or 'Miltwaste', or 'Finger ferne', because it is no longer than a manne's finger; or 'Scale ferne', because it is all full of scales on the inner syde." (Turner 1568; quoted in Step & Jackson 1945, p. 57). ‘Ceterach’ or ‘Chetherak’ is said to be of Arabic origin, probably handed down by apothecaries who used it as a medicine for troubles of the spleen and liver (Step & Jackson 1945).

The name 'Miltwaste' refers to the spleen (the 'milt'), the suggestion being that animals eating the fern rootstock (although considering how and where the plant grows, this would in reality seem almost impossible for them to achieve), were said to suffer wastage of their spleen and liver (Step & Jackson 1945). The origin of other names like 'Rustyback', 'Brown-back' and 'Scale-fern' are obvious to anyone examining the plant. 'Stone-fern' reflects the habitat in which it grows.

The name 'Saxifrage' (ie 'Stone-breaker') has also been applied to this fern. This name first appears in 1526 in a work printed by Peter Treveris in Southwark, London entitled The grete herball, an anonymous early English translation of an anonymous French work published in Paris c 1498, known under the title Le grant herbier en françoys (Henrey 1975, Volume 1, page 6 & pp 15-22). In this work, 'Saxifrage' is simply illustrated as a fern, which was subsequently identified by Britten and Holland (1886) as Ceterach officinarum. This name could refer to any rock or wall growing fern, including several members of the genus Asplenium. C. officinarum was previously called Asplenium ceterach L., and occasionally it reverts to this name (eg Jermy & Camus 1991). The idea behind the name 'Saxifrage', whatever plant it is applied to, is that they assist the disintegration of the rocks on which they grow. Another English name is simply 'Common Spleenwort' (Grieve 1931).

Uses

The appearance of the frond was considered spleen-like, and following the ancient ‘Doctrine of Signatures’ it could therefore be used to treat ailments of the spleen and other viscera. For instance, an infusion of the fronds was perscribed by herbalists to treat gravel in the liver and spleen (Grieve 1931, pages 302-3).

Threats

Re-pointing of bridges, or replacement of old bridges by new ones.