Umbilicaria phaea

Umbilicaria phaea is a brown, umblicate foliose lichen that grows up to 6 cm in diameter, sometimes in colonies covering large patches of desert rocks.[1]^:127 [2] One variety that grows in northern California is brilliant red.[1] It is (monophyllous) with a single 1 – 5 cm flattish leaf-like cap on top of an anchoring stem(umblicate).[2] The leaflike top is smooth with some lobes, roughly circular, thin, and brittle.[2] The lower surface is light gray to light brown.[2] It has up to 2.5 mm black circular to slightly polygonal spots that are the fruiting bodies (apothecia), slightly sunken into the main nonfruiting body part (thallus).[2] It grows on siliceous boulders in very dry climates of western North and South America, where it is usually the most common member of its genus.[2]

Umbilicaria phaea
Scientific classification
Kingdom:	Fungi
Division:	Ascomycota
Class:	Lecanoromycetes
Order:	Lecanorales
Family:	Umbilicariaceae
Genus:	Umbilicaria
Species:	U. phaea
Binomial name
Umbilicaria phaea

References

1. Field Guide to California Lichens, Stephen Sharnoff, Yale University Press, 2014, ISBN 978-0-300-19500-2
2. Lichen Flora of the Greater Sonoran Desert Region. Vol 2, Nash, T.H., Ryan, B.D., Gries, C., Bugartz, F., (eds.) 2001,