Buellia norstictica Imshaug in sched.

Thallus: dispersed whitish areoles on a black prothallus.
Apothecia: immersed
Epihymenium: olive-green
Hymenium: greenish at base
Ascospores: 14.5-18 x 8 Ám

Chemistry: atranorin, nostictic acid by TLC

Description & Ecology:
Several collections from the Falkland Islands.

This species is superficially similar to Rhizocarpon immersum (see below) from which it is separated by its simple paraphyses and Lecanora-type asci.
Probably a synonym of Buellia spuria, although the norsticitic acid chemotype may deserve some taxonomic status, possibly as a separate geographical variety (F. Bungartz pers. comm.)

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