Foliose lichen, Xanthoria parietina, on hawthorn

Foliose lichens are some of the largest and perhaps most complex lichens. The thallus generally forms flat, leaf-like lobes.

The first PiP shows a Crustose lichen, possibly Lecanora muralis, growing on a sandstone wall. The thallus forms a crust over the substrate and is firmly attached to it. Consequently, the lichen normally cannot be collected intact without collecting a portion of the substrate along with it.

The second PiP shows a Fruticose lichen, possibly Usnea subfloridana growing an a larch tree. The thallus is extended up into a tufted or pendant branched structure and is attached to the bark by a basal holdfast.