A synopsis of the genusArthothelium(Arthoniales) in Tasmania

Abstract

AbstractThe genusArthotheliumA. Massal. in Tasmania comprises ten species. Five of these are described as new:A. bacidinumKantvilas, a saxicolous, littoral species with subglobose apothecia, non-macrocephalic ascospores, 25−40 × 11−19 μm, and containing the pigment Endoaurantiacum-gold which yields a K+ red reaction;A. insolitumKantvilas, lichenicolous in rainforest and characterized by subglobose apothecia, very large, non-macrocephalic ascospores, 50−80 × 22−40 μm, and containing the pigment Interveniens-brown which reacts K+ olive green;A. macounioidesKantvilas, corticolous in wet forest and characterized by sessile, convex apothecia, macrocephalic ascospores, 29−42 × 11−18 μm, and containing the pigment Endoaurantiacum-gold;A. magenteumKantvilas, a common wet forest epiphyte with applanate apothecia, non-macrocephalic ascospores, 25−55 × 11−22 μm, and containing a unique maroon-red, K+ pink pigment; andA. subtectumKantvilas, a saxicolous species with convex apothecia, macrocephalic ascospores, 22−36 × 9−14 μm, and containing Endoaurantiacum-gold. The New Zealand speciesA. endoaurantiacumMakhija & Patw. andA. suffusum(C. Knight) Müll. Arg., and the AustralianA. velatiumMüll. Arg. are recorded for Tasmania for the first time. The namesA. obtusulum(Nyl.) Müll. Arg.,A. pellucidum(C. Knight) Müll. Arg. andA. polycarpumMüll. Arg. are considered synonyms of the widespreadA. ampliatum(C. Knight & Mitten) Müll. Arg.Arthothelium feraxMüll. Arg. is a synonym ofA. interveniens(Nyl.) Zahlbr. andA. subspectabileVĕzda & Kantvilas is a synonym ofA. suffusum. The sole record ofA. macrothecum(Fée) A. Massal. from Tasmania is found to be based on a misidentification. A key to the species is provided. The importance of apothecial pigments, apothecial morphology and ascospore septation is discussed, and three pigments are characterized by their appearance in water and other standard media.