ejb422's picture


Observed: 4th June 2012 By: ejb422
S159 Neighbourhood Nature - current student

Found on lampost in urban area under shade of adjacent tree.


Caution: Do NOT use iSpot to identify fungi to eat!

Some fungi are very poisonous so a mistaken ID could have serious consequences.

Species interactions

No interactions present.

Species with which Common Orange Lichen (Xanthoria parietina) interacts


ejb422's picture

Identification of species and location

This is going to prove more difficult than I thought.

AlanS's picture

Ha ha!

I have been doing lichens for several years and I feel I am only now starting to get the hang of my local urban species (and am probably deluding myself).

However, you have a pretty standard urban concrete community here. Xanthoria parietina is reasonably straight forward when covered with apothecia (but X. calcicola, with few or no apothecia and the centre of the thallus densely wrinckled or covered by small, spherical isidia, can look similar and is often overlooked.) The slender-lobed pale grey lichens are Physcia adscendens and P. tenella, and the duller-coloured, more appressed, rounded thalli are Phaeophyscia orbicularis. These are all nitrophilous ("nitrogen loving") species, benefitting in this case probably from nitrogen oxides produced from vehicle exhausts.

There will be smaller species, including the tiny discs of Lecanora dispersa, and very likely, with a good lens, Lecania erysibe and Rinodina oleae (gennarii) - both with tiny blackish discs with paler margins.

Your concrete post has some yellowish patches that will most likely be a Caloplaca of some sort (testing purple with potassium hydroxide) or a Candelariella (not purple with KOH). The two likely Candelariella species (aurella and vitellina) are best separated on microscopic characters. Caloplaca, notably those that have been called "citrina" are currently a nightmare - this name having covered several species, with two of the most common currently not in Britsh books.

If I get time, no promises, I'll be updating my website with some of these tiny things in the near future. (Praise to Canon's MP-E ultra-macro lens.)