Sunday, November 22, 2020

Asplenium ceterach – Rustyback Fern

Asplenium cetarach botanical drawing (www.biolib.de).Photo of Asplenium cetarach on a wall in Bergamo.Photo of Asplenium cetarach on a wall in Bergamo.Photo of Asplenium cetarach on a wall in Bergamo.
Left: Asplenium cetarach botanical drawing (www.biolib.de).
Center and right: Photos of Asplenium cetarach on a wall in Bergamo.

The upside of the coronavirus lockdown (November 2020 edition) is that we've spent more time walking and exploring parts of Bergamo we usually don't. Case in point, we found ourselves on the Scaletta Scorlazzino, a beautiful and long stair climb up the southern slopes below Via Sudorno. On these sun-exposed walls we ran into Asplenium ceterach, commonly known as the Rustyback fern, another good candidate for a "wall plants of Bergamo" post.

Unlike many other ferns, A. ceterach likes sun and requires little humidity. The Rustyback fern is also known "as a resurrection plant due to its ability to withstand desiccation and subsequently recover on rewetting."[ref] That's an apt metaphor for the on and off again lockdowns and looking forward to getting through this pandemic intact.

The family Aspleniaceae (recall the taxonomy: kingdom, clade, class, order, suborder, family, genus, species) is a family of ferns called spleenworts for their approximate resemblance to spleens. In two previous posts we talked about two other wall-loving ferns in this family: Asplenium ruta-muraria and Asplenium tichomanes, that both look similar to A. ceterach.

Rustyback is found in Western and Central Europe, including the Mediterranean region. It is commonly found growing in fissures in limestone and dolomite rock and on the mortar of stone and brick walls, as in these photos. The English common name Rustyback – according to Wikipedia – is due to the orange-brown hairs (trichomes) on the backside of the fronds.

In Italian, this fern is called la cedracca. According to Treccani, this Italian word derives ultimately from the Persian word shītarak.


A photo of Asplenium cetarach on a sunny wall of the Scaletta Scorlazzino in Bergamo.The underside of the an A. cetarach frond.
Left: A photo of Asplenium cetarach on a sunny wall of the Scaletta Scorlazzino in Bergamo.
Right: The underside of the an A. cetarach frond.

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