Clarification of Amanita umbrinella (Agaricales: Amanitaceae: Amanita sect. Amarrendiae) and three new, related agaricoid species from Australia

Amanita umbrinella E.-J.Gilbert & Cleland is re-described based on the lectotype and collections from around Australia; Amanita umbrinelloides A.E.Wood is synonymised with it. Additional information is provided for A. muriniflammea Tulloss, A.M.Young & A.E.Wood. Three closely related species are described herein as: Amanita horizontalis E.M.Davison & Giustiniano, Amanita doreta E.M.Davison & Giustiniano, and Amanita cinereoalba E.M.Davison, Giustiniano & P.S.Catches. Amanita horizontalis differs from A. umbrinella in its taller habit, in having a membranous partial veil that is horizontal when young, ellipsoid to elongate spores, and in molecular sequences. It occurs in South Australia, Tasmania, Victoria and Western Australia. Amanita doreta is similar in appearance to A. horizontalis and has similar shaped spores; but it differs in molecular sequences and occurs in Western Australia. Amanita cinereoalba is a grey, small to medium sized species with a descendent, evanescent partial veil, and large, broadly ellipsoid to ellipsoid spores. It differs in molecular sequences and occurs in South Australia. The 28S gene region indicates A. cinereoalba is closely related to the sequestrate species A. grandis (Bougher) Justo and A. oleosa (Bougher & T.Lebel) Justo.