Asplenium ceterach
Asplenium ceterach (syn. Ceterach officinarum) is a fern species commonly known as rustyback. Description. It is characterised by a short rhizome which gives rise to several green fronds that have a pinnated lamina with trichomes on the abaxial (lower) surface, but not the adaxial (upper) one. These trichomes (hairs) are orange-brown in colour, hence the name "rustyback". The petiole is shorter than the corpus of the leaf. Taxonomy. A global phylogeny of "Asplenium" published in 2020 divided the genus into eleven clades, which were given informal names pending further taxonomic study. "A. scolopendrium" belongs to the ""Ceterach  subclade of the ""Phyllitis" clade". Members of the "Phyllitis" clade have undivided or pinnatifid leaf blades with a thick, leathery texture, persistent scales on their stalk, and often possess anastomosing veins. Members of the "Ceterach" subclade have pinnatifid leaves, usually with a thick covering of hairs and/or scales and irregularly anastomosing veins. Distribution and habitat. This species is found in Western and Central Europe, including the Mediterranean region, in the Arabian Peninsula and in temperate Asia as far east as Tibet. It is associated with fissures in carbonate rocks and also grows on the mortar of stone and brick walls . Can be found growing up to 2700 metres above the sea level, although it prefers mountainous locations, where it is usually found growing in sunny rocky walls and slopes. Unlike many others, this fern likes growing in full sun, and requires little, if any, humidity. Traditional uses. It has been widely used for making infusions as a diuretic. Desiccation tolerance. This fern is well known as a resurrection plant due to its ability to withstand desiccation and subsequently recover on rewetting. It has been shown that this is in part due to its high concentrations of phenolic compounds such as  chlorogenic acid and caffeic acid which allow it to negate the destructive capacity of the reactive oxygen species generated by the drying process; the concentrations of these phenols decrease during the dehydration process. Enzymes such as peroxidase and polyphenol oxidase have also been shown to be important in allowing this fern to cope with desiccation; the concentrations of these enzymes increase when the fern is subjected to water shortages. References.