Abstract
Foliicolous material of the lichenized genus Porina was collected in different types of forest in Thailand. Three new species were discovered: P. subatriceps Naksuwankul & Lücking, characterized by a yellowish brown, K+ reddish involucrellum and oblong, 7–11–septate ascospores, P. lumbschii Naksuwankul & Lücking, with large, muriform ascospores, and P. thailandica Naksuwankul & Lücking, having, small, oblong, 3–septate ascospores and a dark brown to black, K–involucrellum, morphologically close to P. homala and P. subhomala which differ by having 7–septate ascospores. An artificial key to species for a total of 55 taxa found in Thailand is provided and 20 new records are listed for the country.