Phylogenetic hypotheses: Cladoniaceae, Stereocaulaceae, Baeomycetaceae, and Icmadophilaceae revisited

Abstract

Parsimony analyses of SSU rDNA sequences were conducted to examine phylogenetic relationships of selected genera within the families Cladoniaceae, Stereocaulaceae, Icmadophilaceae and Baeomycetaceae (lichen-forming ascomycetes). The analyses included 93 taxa (84 species) representing various groups of ascomycetous fungi. Analyses of the matrix with pre-aligned sequences were performed using heuristic and parsimony ratchet searches, and support values for the same matrix were calculated using parsimony jackknifing. The results support the recognition of the four families. Cladoniaceae are recircumscribed to accommodate Cladia, Cladonia, Heterodea, Metus, Pilophorus, Pycnothelia, Ramalea, Thysanothecium and the newly erected genus Carassea. Myelorrhiza is excluded from the family, while the status of other potential members, Calathaspis, Gymnoderma s.str. and Squamella, remains unresolved. Baeomycetaceae include Baeomyces and Phyllobaeis. Stereocaulaceae include Stereocaulon only, although the status of Muhria is still unclear. Finally, Icmadophilaceae include Dibaeis, Endocena, Knightiella, Icmadophila, Siphula and Thamnolia, while the status of Pseudobaeomyces and Siphulella requires further elucidation. The genus Cladonia appeared to be a polyphyletic assemblage, and accordingly, a new genus Carassea S. Stenroos, gen. nov., represented by C. connexa (Vain.) S. Stenroos, comb. nov., is described. Carassea is most closely related to Pycnothelia and Metus in the Cladoniaceae. Siphula, represented in the present analysis by six species, is not monophyletic, and is in need of reclassification.