Xanthoparmelia Ceresella

''Xanthoparmelia'' (commonly known as green rock shields or rock-shield lichens) is a genus of foliose lichen in the family Parmeliaceae.Field Guide to California Lichens, Stephen Sharnoff, Yale University Press, 2014, ''Xanthoparmelia'' is synonymous with ''Almbornia'', ''Neofuscelia'', ''Chondropsis'', ''Namakwa'', ''Paraparmelia'', and ''Xanthomaculina''. This genus of lichen is commonly found in the United States, as well as Australia, New Zealand and Ecuador.

The name means 'golden yellow parmelia'. The photobiont (photosynthetic partner) is ''Trebouxia'' (a genus of green algae).

Identification

Distinguishing between species involves how much they are attached to the substrate, whether or not isidia are present, lower surface color, and chemical spot tests. All members of the genus react to spot test as K-, KC+ yellow, with medulla reaction varying from species to species.

Species

Species include:
* '' Xanthoparmelia chlorochroa''
* ''Xanthoparmelia conspersa'' (''Parmelia conspersa'')
* ''Xanthoparmelia cumberlandia''
* '' Xanthoparmelia lavicola'' - a foliose (leaf-like) lichen found on basalt
* ''Xanthoparmelia lineola''
* '' Xanthoparmelia maricopensis''
* '' Xanthoparmelia mexicana''
* '' Xanthoparmelia metastrigosa''
* '' Xanthoparmelia mougeotii'' (''Parmelia mougeotii'')
* '' Xanthoparmelia nana''
* '' Xanthoparmelia pokornyi''
* '' Xanthoparmelia subramigera''
* '' Xanthoparmelia scabrosa''
* '' Xanthoparmelia tinctina''

Taxonomy

''Xanthoparmelia'' was originally conceived of as a section of the genus '' Parmelia'' by Brazilian lichenologist Edvard August Vainio in 1890, to accommodate yellow species with narrow lobes. Mason Hale considered that the combination of traits including the presence of the cortical pigment usnic acid, and the microscopic structure of the upper cortex were sufficient criteria to segregate ''Xanthoparmelia'' from the genus ''Parmelia''. He formally transferred 93 species, including the type, ''Xanthoparmelia conspersa''.

In a 2004 study, molecular analysis was used to help revise the classification of parmelioid lichens containing ''Xanthoparmelia''-type lichenan. This analysis demonstrated that several genera previously segregated from ''Xanthoparmelia'' on the basis of physical characteristics did not form distinct clades within ''Xanthoparmelia'', and so ''Neofuscelia'', ''Chondropsis'' and ''Paraparmelia'' were synonymized with ''Xanthoparmelia''. As a result of this work, 10 new species were published, and 129 new combinations into ''Xanthoparmelia'' were proposed. Similarly, three south African genera, ''Almbornia'', ''Namakwa'', and ''Xanthomaculina'', were synonymized with ''Xanthoparmelia'' after the limits of the genus were further explored and refined with molecular phylogenetics. ''Karoowia'', a genus that was characterized by features such as its subcrustose growth form and its presence of an arachiform vacuolar body in the ascospores, was synonymised with ''Xanthoparmelia'' when it was shown that its species cluster in different clades nested within ''Xanthoparmelia''. The genus ''Omphalodiella'', proposed by Aino Henssen in 1991 to contain the Patagonian species ''Omphalodiella patagonica'', has since been shown to lie within ''Xanthoparmelia''.

Gallery

Image:Xanthoparmelia_plittii_(EU).jpg, '' Xanthoparmelia plittii''
Image:Lichen_reproduction1.jpg, Unidentified ''Xanthoparmelia'' sp.
File:Xanthoparmelia subramigera.jpg, '' Xanthoparmelia subramigera'' growing on an asphalt shingle roof in Maryland, United States

References

{{Taxonbar, from=Q9397450

Lichen genera
Lecanorales genera
Taxa named by Edvard August Vainio