Studies on the lichen family Thelotremataceae in Tasmania. The genus Chroodiscus and its relatives

The Tasmanian species of the family Thelotremataceae with thin-walled ascos pores and exfoliating, chroodiscoid apothecia are studied in derail. Proble ms in the delimitation of genera are discussed, and characters such as the morphology of the apothecia, structure and form of the exciple, presence of periphyses, ascus structure, ascospore morphology and thallus chemistry ar e evaluated. The concept of the typically foliicolous genus Chroodiscus (Mu ll. Arg.) Mull. Arg. is expanded to include corticolous and terricolous spe cies, and the new taxa C. asteliae Kantvilas & Vezda, C. australis Kantvila s & Vezda, C. australis subsp. tasmanicus Kantvilas & Vezda, C. lamelliferu s Kantvilas & Vezda and C. minor Kantvilas & Vezda are described and illust rated. The related Australasian species, C. megalophthalmus (Mull. Arg.) Ve zda & Kantvilas is also treated. Two new genera are also described. Pseudor amonia Kantvilas & Vezda, based on the Venezuelan species, P. stipitata (Ve zda & Henel) Kantvilas & Vezda, is introduced to accommodate P. richeae Kan tvilas & Vezda; Topeliopsis Kantvilas & Vezda is described to include the T asmanian taxa, T. muscicola Kantvilas & Vezda and T. rugosa Kantvilas & Vez da, and the North American species T. toensbergii Vezda & Kantvilas. (C) 20 00 The British Lichen Society.