Three species of Hypomyces growing on basidiomata of Stereaceae

Abstract

Of the eight species of Hypomyces that occur on basidiomata of Stereum species, only H. sympodiophorus grows exclusively on members of this genus. Morphologically similar fungi were found on species of Xylobolus, a genus closely related to Stereum. These are described as two new species of Hypomyces: H. thailandicus, collected on Xylobolus cf. illudens in Thailand; and H. xyloboli, on X. frustulatus and X. subpileatus in the eastern United States. These three species are unusual in Hypomyces because of their almost indistinguishable anamorphs. In parsimony analysis of LSU nuclear rDNA sequences, the three species growing only on Stereaceae do not form a monophyletic group but their constrained monophyly is not rejected either. A morphologically similar anamorphic species, Sibirina gamsii, included in the study, is transferred to the genus Cladobotryum.

• Cladobotryum
• fungicolous fungi
• Hypocreales
• rDNA
• Sibirina
• Stereum
• systematics
• Xylobolus

My sincere thanks to Dr. Gary Samuels for improving the text and making the microtome sections of perithecia, to Prof. Erast Parmasto for identifying the hosts and revising the manuscript and to Dr. Walter Gams who corrected the Latin descriptions. I am grateful to Dr. Lisa Castlebury for the opportunity to work under her supervision in the molecular lab at the Systematic Botany and Mycology Laboratory, Beltsville, and to Dr. David Farr for sharing his great expertise in digital imaging. Dr. Sarah Dodd also gave valuable hints for the work with DNA. Samuels and Jacques Fournier are thanked for providing specimens, and Dr. Wendy Untereiner is thanked for her many editorial suggestions. This study was supported in part by the United States National Science Foundation (PEET) Grant 9712308, “Monographic Studies of Hypocrealean Fungi: Hypocrea and Hypomyces” to the Pennsylvania State University Department of Plant Pathology and the Estonian Science Foundation Grant No. 4994.