Flora of New Zealand Series

Thallus crustose or squamulose, lacking cephalodia, distinctly effigurate to ± spreading. Photobiont green, Protococcus. Apothecia adnate, lecanorine, constricted at base. Asci cylindrical or subcylindrical, 8-spored. Paraphyses slender, lax, intricately branched. Ascospores simple, colourless, ellipsoid, or subfusiform, without an epispore. Thallus cortex and thalline exciple C+ red (gyrophoric acid).

Trapelia [Hertel Herzogia 1: 111-130 (1969)] included in the family Trapeliaceae [Hertel Dtsch. bot. Ges. N. F. 4: 171-185 (1970)], with Placopsis and Orceolina, differs from both Lecanora and Lecidea (in which its species have long been included) by the subcylindrical asci and the slender, lax, intricately branched, non-capitate anastomosing paraphyses. It is closely related to Placopsis but differs mainly in the absence of cephalodia. Seven species are known, all of ± cosmopolitan distribution. Several species occur in New Zealand, but the genus is as yet poorly collected and understood. One species is discussed here.