The Verrucaria fuscella group in great Britain and Ireland

Verrucaria canella, V. fuscella and V. polysticta occur in Great Britain and Ireland; these species have been widely confused, and have often incorrectly been called V. glaucina. Similar specimens parasitic on Aspicilia caesiocinerea may belong to an additional, undescribed species. A lectotype is selected for V. fuscella.