Rusavskia elegans (Elegant Sunburst Lichen)

Kingdom:   Fungi
Division:    Ascomycota
Class:        Peltigerales
Order:        Teloschistales
Family:      Teloschistaceae
Genus:       Rusavskia
Species:     R. elegans
Binomial name: Rusavskia elegans
Synonyms: Xanthoria elegans   Taxonomic Swap 20443 (Committed on 2017-02-21)
Common names:  Elegant sunburst lichen

Rusavskia elegans is a lichenised species of fungus in the genus Xanthoria, family Teloschistaceae. Recognized by its bright orange or red pigmentation, this species grows on rocks and has adapted successfully to growth on man-made surfaces from the sea-water spray zone to the boreal forest and in the grasslands of the continental interiors. It can thrive in areas having less than 6 centimetres annual precipitation and can survive submerged in streams for much of the growing season.
Rusavskia elegans has an extremely broad circumpolar and alpine distribution and is found on all continents. 

It was one of the first lichens to be used for the rock-face dating method known as lichenometry. A technique of estimating the age of rock faces by measuring the diameter of the lichen thalli growing on them. After an initial period of one or two decades to establish growth (the ecesis interval), R. elegans grows at a rate of 0.5 mm per year for the first century, before slowing down somewhat.

Photographed on the Tongariro Alpine Crossing  Elevation 1500 m.Xanthoria elegans Crustose Lichen.jpg

Photographed in West Canterbury, South Island  Elevation 250 m
Xanthoria elegans Elegant sunburst lichen-001.jpg  

Orange coloured Rusavskia elegans
Xanthoria elegans Elegant sunburst lichen.jpg

Thanks to Wikipedia for text and information: