Parmeliaceae

Parmeliaceae
Parmelia cunninghammii, photographed in New Zealand. Scale bar = 1 cm.
Scientific classification
Kingdom:	Fungi
Division:	Ascomycota
Class:	Lecanoromycetes
Order:	Lecanorales
Family:	Parmeliaceae Zenker (1827)
Type genus
Parmelia Ach.

The Parmeliaceae is a large and diverse family of Lecanoromycetes. With over 2000 species in roughly 87 genera, it is regarded as the largest family of lichen forming fungi. The most speciose genera in the family are the well-known groups: Xanthoparmelia (800+ species), Usnea (500+ species), Parmotrema (350+ species), and Hypotrachyna (190+ species).

Nearly all members of the family have a symbiotic association with a green alga (most often Trebouxia spp., but Asterochloris spp. are known to associate with some species). The majority of Parmeliaceae species have a foliose, fruticose, or subfruticose growth form. The morphological diversity and complexity exhibited by this group is enormous, and many specimens are exceedingly difficult to identify down to the species level.

The family has a cosmopolitan distribution, and can be found in a wide range of habitats and climatic regions. This includes everywhere from roadside pavement to alpine rocks, from tropical rainforest trees to subshrubs in the arctic tundra. Members of the Parmeliaceae can be found in most terrestrial environments.

Based on several molecular phylogenetic studies, the Parmeliaceae as currently circumscribed has been shown to be a monophyletic group. This circumscription is inclusive of the previously described families Alectoriaceae, Anziaceae, Hypogymniaceae, and Usneaceae, which are all no longer recognised by most lichen systematists. However, despite the family being one of the most thoroughly studied groups of lichens, several relationships within the family still remain unclear. Phylogenetic analysis tentatively supports the existence of six separate clades in the family:

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