Taxon sampling

The recently described genus Hyperdermium (Sullivan et al., 2000) exhibits a novel anamorph that the authors compared to the Hypocrealean anamorph, Cylindrocarpon. It produces simple aculeate phialides and the conidia are multiseptate and accumulate in a microsclerotium-like mass which apparently functions as a diaspore. Sullivan et al. (2000) inferred a relationship between Hyperdermium and Cordyceps militaris based on molecular data. Further taxon sampling is needed to elucidate the nearest relatives of Hyperdermium. 

The examples detailed above (and that of Phoronis vancouverensis") illustrate the well known dangers inherent in PCR-based analyses and underline the need for a well-chosen, replicated taxon sample and/or genetically independent confirmation of novel hypotheses of relationship. Also, one substantial procedural flaw in our previously published work (Cohen and Gawthrop, 1996, 1997 Cohen et ai, 1998a,b) must be noted parsimony bootstrap analyses were performed after character reweighting on the most parsimonious tree obtained by successive approximation bootstrap frequencies were therefore somewhat inflated (Liden, 1999). 

The phylogenetic position of Mittenia complanata is consistent with inclusion in the haplolepidous mosses rather than diplolepidous-altemate mosses, from a combined evidence analysis using Funaria as an outgroup. Therefore, the use of Mittenia as an outgroup is justified in the atpB analysis. Taxon sampling prevents a more exact inference of its nearest relatives. 

The emphasis of the present analyses is on mosses, in particular pleurocarpous mosses, and although our analyses include a taxon sample covering all major groups of land plants, relationships among non-moss taxa will not be discussed here. 

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