Lichen disappearing

[HeyWayne]

Not sure if this is in the right place or not, apologies if not.

I'm sure I saw something fairly recently that lichen is/was considered endangered as it was higly suceptable to pollution. I remember seeing in on the concrete fence posts in the gardens as a child. Hadn't really considered not seeing it until someone mentioned you don't see it very often any more (a bit like white dog poo I guess).

Anyway, we have a little Acer of some description in a large tub on the patio and I noticed that along with the buds that are appearing, there are several patches of lichen also appearing. I'm sure it's harmless, but does anyone know anything about lichen at all?

[Flummery]

It's harmless and is a good indication of air quality. Round here it had definitely increased over the past few years. No coal fires for one thing.

[lainey lou]

White dog poo.....can't remember when I last saw one of them.......