Lichen It

Funny how you can look at something regularly and still not see everything about it. I rechecked an old wooden bench in our garden that I'd already looked at multiple times and discovered a single colony of Flavoparmelia caperata growing amongst the other lichen colonies there. Given how distinctive it is, I'm surprised I didn't notice it earlier. This leafy lichen (a type called "foliose" in official lichen lingo) is a rather unique yellow-grey colour when dry (hence Flavoparmelia — flavo meaning "yellow") and a bright apple green when wet. This is a baby colony, measuring a bit less than an inch wide; at maturity, it may stretch across more than 8 inches. Its lobes are very wide (up to 1 cm or 1/2-inch) and quite wrinkly and contorted. They'll become even more so as the lichen matures. The central surface is already sprinkled with coarse soredia (lichen's way of spreading itself) even though it's a young colony. That little pink spot on the lichen's left side is a hostile fungus, one of the lichenicolous species that survives only by parasitizing a lichen.

According to Frank Dobson's seminal Lichens: An Illustrated Guide to the British and Irish Species, Flavoparmelia caperata is "very common on acid-barked deciduous trees" in the south of England. I guess old wooden benches are the next best thing! It's also found on rocks, roofs and mosses (which it overgrows). It has been badly impacted by high sulfur dioxide levels in the UK, but now that we're getting air pollution levels under better control, it's beginning to recolonize some areas where it had previously been eradicated. It's even been found on the grounds of Buckingham Palace!