Asplenium ceterach – October 27th 2025 – Rustyback
Linnaeus named this fern Asplenium ceterach in the year 1753 and that is the name we use today. However, in the 1991 edition of Stace’s New Flora of the British Isles (the first edition) and many older books its name is Ceterarch officinalis. Plants with the specific name officinalis were traditionally medicinal plants as the word comes from ‘officina’ which was the storeroom in a monastery where medicines were kept.
Asplenium ceterach. Illustration from Scandinavian Ferns by Benjamin lgaard and Kirsten Tind, Rhodos, 1993, accessed via the Hardy Fern website https://hardyfernlibrary.com/ferns/tind/asplenium%20ce.jpg
Aspleniums have always been called ‘spleenworts’ because their fronds were said to resemble the human spleen The traditional belief was that a plant’s appearance is a sign from God indicating the ailment it can cure (‘the doctrine of signatures’). Hence, in 1597 the herbalist John Gerard wrote
“…the leaves boiled in wine and drunk by the space of forty days, do take way infirmities of the spleen; help the strangury, and yellow jaundice, cause the stone in the bladder to moulder and pass away, all which are performed by such things as be of thin and subtle parts: he addeth likewise that they slay the hicket, or yexing, and also hinder conception, either inwardly taken, or hanged about the party, and therefore, saith Pliny, Spleenwort is not to be given to women, because it bringeth barrenness”.
I needed to look up the meaning of three of these obsolete medical terms1.
The tincture of this fern can be purchased from a well-known internet supplier, although the advertisement does not make any claim of medicinal efficacy. Asplenium ceterach does however contains a wide range of phytochemicals, many of which are biologically active (see here). These compounds may be responsible for the fern’s notable antioxidant properties, which may be connected to its reputation as a ‘resurrection plant’ (it survives desiccation, see the last paragraph).
This is what you can buy. The word Spaccapietra implies ‘stonebreaking’ and may refer to certain urinary malfunctions.
It is a native plant in Britain, also in much of Europe and some of North Africa. It is however locally extinct in Poland, although it was historically found there and today it can be found surviving in Botanical Gardens. In Britain it is most common in the South-west. Evidently it was always so, as we read how William Turner, the 16th Century “Father of English botany”, wrote “..I heare say it is plentuous in the west country here in England”.
Asplenium ceterach on limestone at the Burren, Co Clare, Ireland. Image: Chris Jeffree.
Asplenium ceterach is found growing in locations where calcium carbonate forms the substrate. In Scotland I have seen it on the lime-based mortar of old walls. It also occurs on limestone geologies, including limestone pavement (especially at the Burren in western Ireland). It likes the crevices in limestone cliffs and limestone screes.
It is a small evergreen fern; usually its fronds are no more than 15 cm long. One of its early names was ‘Finger-fern’, but its usual English name is ‘Rustyback’ referring to the rusty-coloured scales on the underside of the leaf. The scales protect the sporangia, which produce their spores more-or-less continually from April to October. More details of the structure can be viewed at this rather new website https://hardyfernlibrary.com/
Dessicated specimen of Rustyback Fern from Cazorla in Spain. Image: Chris Jeffree.
Asplenium ceterach is one of those species with a remarkable ability to recover from dehydration; they are known as ‘resurrection plants’. The phenomenon is known throughout the plant kingdom, most notably in bryophytes but also in ferns and flowering plants, although the mechanisms involved are not always the same. One careful study tried to link the recovery to the wide range of phytochemicals that spleenworts contain (Farràs et al 2022). In some cases, the recovery requires a reconstruction of much of the photosynthetic machinery. Research has so far failed to transfer the capacity for resurrection to a crop plant, probably because there are so many genes involved.
Distribution patterns of Asplenium ceterach. Left: British Isles from BSBI/Maps, top right: native range (green) and extinction (red), lower right: global distribution according to GBIF.
Note
1strangury means difficulty in urinating, a hicket seems to be a love-bite, and yexing may be hiccups.
Reference consulted
Farràs Martínez, A et al. (2022) Exploring wild Aspleniaceae ferns as safety sources of polyphenols: the case of Asplenium trichomanes L. and Ceterach officinarum Willd. Frontiers In Nutrition, 9, 994215.
©John Grace
