Zdunczyk, A./ M. Dziedzic/ M. Kukwa 2012: The lichen genus Pertusaria in Poland II. Secondary chemistry of P. Flavida. - Folia Cryptogamica Estonica49: 77-81. [RLL List # 233 / Rec.# 35081] Abstract: This paper presents a study on a chemical variation of Pertusaria flavida in Poland. Six chemotypes were determined in the studied material, of which chemotypes IV, V and VI were never reported before. All of them produce thiophaninic acid as the diagnostic metabolite for the species and this is the only major substance in chemotype I. Chemotype II contains in addition also 2'-O-methylperlatolic acid (± confluentic acid), whereas chemotype III stictic acid complex (± minor or trace amounts of norstictic acid). Chemotype IV is characterized by the presence of 2'-O-methylperlatolic acid and stictic acid complex (± norstictic acid in minor to trace amounts). Chemotype V produce norstictic acid as a major additional substance and chemotype VI contains 2'-O-methylperlatolic acid together with norstictic acid. Chemotype II was the most common chemotype (c.75 % of specimens) in studied material. Distribution maps are presented for all chemotypes.