I decided to acetone the red lichens today, because a greenbottle had been walking around and possibly on them.
As expected, the red pigment (probably chiodectonic acid, but since the taxonomy is unclear I can't be sure) rapidly dissolved, eventually causing the big thallus to turn brownish green and the smaller fragments to be completely white. If I recall correctly the white compounds do not dissolve in acetone, and since the big one had less of them it would explain the difference.
Then the big thallus (not the others) turned purple. I can only hope it wasn't killed by the chemical reaction. Edit: even violent rinsing failed to remove the purple; I threw them out.
