Parmeliaceae thalli are most often foliose, fruticose or subfruticose, but can be umblicate, peltate, caespitose, crustose, or subcrustose. OneTwo genusgenera, ''[[Nesolechia (fungus)|Nesolechia]]'',isand even''[[Raesaenenia]]'', acontain [[lichenicolous fungus|lichenicolous fungi]]. They can be a variety of colours, from whitish to grey, green to yellow, or brown to blackish (or any combination therein). Many genera are lobe forming, and nearly all are heteromerous (which are [[corticate]] on both sides). Species are usually rhizinate on the lower surface, occasionally with holdfasts, rhizohyphae, or a hypothallus. Only a few genera have a naked lower surface (for example ''[[Usnea]]'', ''[[Hypogymnia]]'' and ''[[Menegazzia]]''). The upper surface has a pored or non-pored epicortex. [[wiktionary:medulla|Medulla]] is solid, but often loosely woven.<ref name="Elix">Elix, J.A. (1994). Parmeliaceae. Flora of Australia – Volume 55. http://www.environment.gov.au/biodiversity/abrs/publications/flora-of-australia/vol55.html</ref>
