Appearance
Thallus crustose, bright yellow or sometimes tinged greenish, cracking to produce angular to rounded areoles, some of which are semi-circular, curving around the apothecia; apothecia flat, black, in microscopic section with K- exciple, and with an olive brown, K- or K+ green epithecium.References:
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http://www.lichens.lastdragon.org/Rhizocarpon_lecanorinum.html