Molecular systematics of the ascomycete genus Farrowia (Chaetomiaceae)

The genus Farrowia D. Hawksworth was established for members of the Chaetom iaceae with Botryotrichum-like anamorphs and long-necked ascomata, but the separation of Farrowia from Chaetomium Kunze has been questioned by mycolog ists who did not consider these characters to be significant at the generic level. The recent description of a species of Chaetomium with an aleurioco nidial anamorph and long-necked ascomata prompted us to explore this questi on employing molecular characters. We sequenced a portion of the nuclear la rge ribosomal subunit rRNA gene (28S) of members of the Sordariales includi ng species of Chaetomium, Farrowia and Thielavia. Phylogenetic analyses con firmed the monophyly of the Sordariales and the close relationship of Aporo thielavia leptoderma to the genus Chaetomium. A sequence-based phylogeny id entified a well-supported clade that included Chaetomium floriforme, Chaeto mium sphaerale, members of the genus Farrowia, and longicollous species of Chaetomium with aleurioconidial anamorphs. A clade containing Chaetomium br evipilium, Chaetomium cuyabenoensis, Chaetomium homopilatum and species of Farrowia was inferred from the analysis of morphological characters, but th is data set was found to be incongruent with the 28S sequence data. While t hese results are in agreement with the hypothesis that species of Farrowia comprise a group of closely related taxa, they do not provide strong suppor t for the recognition of the genus Farrowia.