Plate 27 



A. UMBILICARIA PUSTULATA (L.) HOFFM. 



Many plants on rock, showing the habit of growth and the round to irregular, pustulate 



thalli. Natural size. 



B. PERTUSARIA VELATA (TURN.) NYL. 



Plant on the branch of a tree, showing the crustose thallus and the apothecia. Enlarged 



\Y\ diameters. 



