A NEW POSITION OF THE CETRARIA-COMMIXTA GROUP IN MELANELIA (ASCOMYCOTINA, PARMELIACEAE)

The Cetraria commixta group, including four species, is transferred to Melanelia Essl., and the following new combinations are made: Melanel ia agnata (Nyl.) Thell comb. nov., Melanelia commixta (Nyl.) Thell com b. nov., Melanelia culbersonii (Hale) Thell comb. nov. and Melanelia h epatizon (Ach.) Thell comb. nov. These new combinations in Melanelia c ould be supported by similarities in the reproductive structures and o ther anatomical characters. Typical Melanelia-asci with a small tholus and a large, broad axial body, dumbbell shaped pycnoconidia and a thi ck, paraplectenchymatous upper cortex put these species together with the brown parmelioid genera. In addition, the species group concerned shows morphologically and chemically similarities particularly to Mela nelia stygia, the type species of Melanelia. A nomenclatural problem r elated to the name M. commixta is discussed in detail.