THE POLYPHYLETIC ORIGINS OF OPHIOSTOMATOID FUNGI

Cladistic analysis was performed on partial sequences from the nuclear -encoded small subunit ribosomal DNA. Taxa were sampled from Ceratocys tis, Ophiostoma and Sphaeronaemella to determine the placement of the inferred monophyletic groups among non-fissitunicate perithecial ascom ycetes. Eight equally most parsimonious cladograms resulted from the a nalysis. In a strict consensus of the eight cladograms, the taxa sampl ed from the three genera did not form a monophyletic group collectivel y. Ceratocystis and Sphaeronaemella formed a clade, which was a sister group to the taxa sampled from the Microascales. Ophiostoma was place d in a separate clade of the tree. These results support the convergen t evolution of long-necked perithecia, scattered evanescent asci and g aleate ascospores. Congruence of anamorph morphology, cycloheximide se nsitivity, cell wall carbohydrate composition and centrum anatomy with the molecular data is discussed.