Phlyctis

Abstract: We provide an updated account on the genera Graphis s.str. and Allographa (formerly included in Graphis ) from Thailand. Four species of Allographa are described as new to science, viz. A. atrocelatoides , which differs from A. atrocelata in having marginata -morph lirellae and a smooth, off-white to beige thallus; A. kansriana , which differs from A. aquilonia in having negrosina -morph lirellae and brownish ascospores; A. schummii , which is characterized in having large, muriform ascospores and an open disc with a cinnabar-red pruina, reacting K+ lemon yellow; and A. sitianoides , which differs from A. sitiana in having immersed to erumpent lirellae and longer ascospores with more numerous septa. Twenty-seven further species are being recombined in the genus Allographa , viz A. acharii , A. aquilonia , A. atrocelata , A. elongata , A. hossei , A. leptospora , A. lumbricina , A. macella , A. marginata , A. norvestitoides , A. nuda , A. pavoniana , A. phaeospora , A. rhizicola , A. rimulosa , A. rufopallida , A. rustica , A. sauroidea , A. seminuda , A. semirigida , A. striatula , A. subdisserpens , A. subdussii , A. trichospora , A. verminosa , A. vestitoides , and A. xanthospora . Seven new Graphis species are described, viz. G. albocarpa , which differs from G. glaucescens in having a laterally to completely carbonized exciple, larger ascospores, and a norstictic acid chemistry; G. emersella , which differs from G. emersa in having hossei -morph lirellae and smaller ascospores with fewer septa; G. khaojoneana , which differs from G. bungartzii in having immersed, unbranched lirellae and smaller ascospores with fewer septa; G. omiana , which differs from G. luluensis in having larger ascospores with more numerous septa and a more complex chemistry relating to the stictic acid aggregate; G. schummiana , which differs from G. anfractuosa in having a laterally to completely carbonized exciple and in the reddish brown pruinose, K+ purple disc; G. sublitoralis , which differs from G. litoralis in having scripta -morph lirellae and in lacking protocetraric acid; and G. subschroederi , which differs from G. schroederi in having smaller ascospores and a laterally carbonized exciple. Four new lirellae morphs are defined, viz. filiformis -morph, balaghatensis -morph, leptogramma -morph and schummiana -morph. After several collecting trips to nineteen provinces of the country, further forty-seven new records of the two genera are added to the most recent checklist of Thai lichens. A key is given to all Allographa and Graphis species so far known for Thailand, as well as close-up photographs of the newly described or newly reported species. The following ten names are removed from the most recent Thai checklist: Graphis concolor ≡ Diorygma junghuhnii , G. fissurinoidea = Diorygma confluens , G. glaucocinerea = Graphis aphanes , G. glaucorufa = Allographa rufopallida , G. irosina = Acanthothecis dialeuca , G. longispora = G. koratensis , Graphis nuda (probably a misidentification), G. ochrocheila ≡ Dyplolabia ochrocheila , G. persimilis = Phaeographis hypoglauca , and G. subrigida = Platygramme platyloma . Graphis siamensis does not belong in this genus but is likely a species of Phlyctis. Graphis diplocheila has a clear hymenium and is a younger synonym of G. streblocarpa and G. dracaenae produces norstictic acid and must therefore kept apart from G. geraensis .