Thank you to Jackie Chambers, UBC Botanical Garden Horticulturist, for both today’s photograph and write-up!
Close inspection of this photo reveals what appears to be the remains of a fern nestled in the rock crevice — there are no obvious signs of life, no green photosynthetic surface is visible, and the leaves are curled inward revealing the rusty coloured trichomes or hairs that line the undersides. At first glance, the fern in this photo may appear somewhat uninspiring; however, Asplenium ceterach (syn. Ceterach officinarum) is a fascinating little plant.
A fern with a preference for dry places, the rustyback fern has an amazing drought tolerance. The vegetative organs of the plants can dry out completely when moisture is lacking, and then revive without injury when water becomes available. When not in its desiccated state, the fern has shiny green fronds that range from 3-20cm long, depending on environment. The leaves are pinnate and leathery, with the rusty-brown hairs hidden on the undersides. It also has a short rhizome, which serves to secure the plant to cracks in walls or rocky surfaces. The Skye Flora‘s page on Asplenium ceterach gives an excellent idea of what the plant looks like when fully hydrated.
Asplenium ceterach has a native range that extends across parts of Europe, northern Africa, and into temperate Asia. This means it can be found in a range of countries and locations: from dry stone walls in parts of the UK to the hot, rocky outcrops along the coast of southern Spain like the one above.
Ferns differ from angiosperms or flowering plants in that they do not rely on flowers or seeds for reproduction — part of their life cycle includes a sporophyte (spore-producing entities) phase and a portion of their life cycle include as gametophyte phase (or gamete-producing organism). This is called alteration of generations, and is described more fully in Wikipedia’s section on ferns.
The interesting lives of spore-bearing plants are celebrated in verse on this website, Cryptogams: Poems, where the author has dedicated a poem to the resurrection abilities of Asplenium ceterach (listed under a synonym, Ceterach officinarum).