Lasallia  

Thallus foliose, monophyllous, plate-like, dorsiventral, attached by a stout, ± central umbilicate stalk. Upper surface densely pustulate, with raised, rounded or oval, convex pustules. Isidia present. Upper cortex composed of densely aggregated hyphal tissue with short cells and ± isodiametric lumina. Lower surface with broad, excavate depressions corresponding to pustules on the upper surface, without rhizines. the lower cortex composed of densely aggregated cartilaginous hyphal tissue. Photobiont chlorococcoid.
Anamorph: conidiomata pycnidia, immersed, with pale brown wall. Conidia bacilliform.
Teleomorph: ascomata apothecia, sessile or ± stalked. Thalline exciple absent. True exciple present, persistent. Disc black, flat, smooth to roughened. Asci elongate-clavate, thick-walled, apical dome K/I+ blue, 1(-2) spored. Ascospores muriform, pale to dark brown.
Chemistry: gyrophoric acid, papulosin, anthraquinones.