Published online by Cambridge University Press: 28 March 2007
A description of the polysporous Buellia dives (Th. Fr.) Th. Fr. is provided. It is distinct from Buellia polysporella (Nyl.) Arnold, with which it has been placed in synonomy, by the lecideine (versus lecanorine) apothecia, the dark brown (versus colourless) hypothecium and the Buellia-type (versus Physcia-type) ascospores. Further, B. polysporella is shown to be conspecific with Rinodina polyspora Th. Fr. and is reduced to synonomy with that species. Buellia dives is reported as new to Norway and Spain and notes on its ecology and distribution are given.