A systematic, morphological and ecological overview of the Clavariaceae (Agaricales)

Abstract

The Clavariaceae is a diverse family of mushroom-forming fungi composed of species that produce simple clubs, coralloid, lamellate-stipitate, hydnoid and resupinate sporocarps. Here we present a systematic and ecological overview of the Clavariaceae based on phylogenetic analysis of sequences of the nuclear large subunit ribosomal RNA (nLSU), including nine from type collections. Forty-seven sequences from sporocarps of diverse taxa across the Clavariaceae were merged with 243 environmental sequences from GenBank and analyzed phylogenetically to determine major clades within the family. Four major clades or lineages were recovered: (i) Mucronella, (ii) Ramariopsis-Clavulinopsis, (iii) Hyphodontiella and (iv) Clavaria-Camarophyllopsis-Clavicorona. Clavaria is paraphyletic, within which the lamellate and pileate-stipitate genus Camarophyllopsis is derived and composed of two independent lineages. The monotypic genus Clavicorona also appears nested within Clavaria. The monophyly of Clavaria and Camarophyllopsis, however, cannot be statistically rejected. We compared differing classification schemes for the genera Ramariopsis and Clavulinopsis, most of which are inconsistent with the molecular phylogeny and are statistically rejected. Scytinopogon, a genus classified in the Clavariaceae by several authors, shares phylogenetic affinities with the Trechisporales. Overall 126 molecular operational taxonomic units can be recognized in the Clavariaceae, roughly half of which are known only from environmental sequences, an estimate that exceeds the known number of species in the family. Stable isotope ratios of carbon and nitrogen were measured from specimens representing most major phylogenetic lineages to predict trophic strategies. These results suggest that most non-lignicolous species feature a biotrophic mode of nutrition. Ancestral state reconstruction analysis highlights the taxonomic significance of at least nine morphological traits at various depths in the family tree.

• biotrophy
• evolution
• morphology
• nutritional mode
• taxonomy

Acknowledgments

This work was financed by a National Science Foundation award DEB-0949517 to PBM and OISE-1012703 to JRM. We would also like to acknowledge NSF DBI-0748955 for research assistantship support to JMB. The Mycological Society of America’s international travel award is gratefully acknowledged for helping to finance travel to present and receive feedback concerning this research. We thank curators and staff from herbaria at the University of Washington (WTU), University of Minnesota (MIN) and University of British Columbia (UBC) for their assistance in loans of specimens. We also thank the associate editor, M. Catherine Aime, and two anonymous reviewers for their valuable critiques and suggestions. Michael Wood and D. Jean Lodge are acknowledged for kindly sharing photographs.