A new Calicium on Ramboldia.

A lichenicolous species, Calicium ramboldiicola , growing on Ramboldia elabens is described. In phylogenetic analyses with 22 Calicium taxa, based on 121 sequences from five DNA regions (mtSSU, Mcm7 , nuITS, nuLSU, β-tubulin), the new species formed a strongly supported clade with C. abietinum and C. verrucosum. Although the ascomata of the new species resemble miniatures of those of C. abietinum , no morphological synapomorphies for this clade were found. Calicium ramboldiicola is known from boreal and hemiboreal areas of northern Europe and north-eastern North America. It is the second known lichenicolous species of Calicium and the first found on a lichen in the Lecanorales. [ABSTRACT FROM AUTHOR]