Published online by Cambridge University Press: 01 October 2010
Buellia rhizocarpica is described from Mexico. This corticolous species is characterized by a yellowish, granulose thallus, the presence of rhizocarpic acid and an unknown pulvinic acid derivative, apothecia containing large amounts of micromera-green together with yellow crystals which react K+ pinkish and by the presence of very small, Buellia-type ascospores. It grows in a well-preserved Pinus hartwegii forest at c. 4000 m altitude at the base of the volcano Popocatepetl.