Hymenotorrendiella clelandii (Leotiomycetes, Helotiales, Helotiaceae) and related species from Australia and New Zealand

Abstract

ABSTRACT Fungi in the class Leotiomycetes are ecologically diverse, including mycorrhizas, endophytes of roots and leaves, plant pathogens, aquatic and aero-aquatic hyphomycetes, mammalian pathogens, and saprobes. Hymenotorrendiella species are often assumed to be saprobic, their fruiting bodies developing on fallen leaves and dead wood but, in many cases, these putative saprobes are found on only a single host. For the leaf-inhabiting species this host specialisation has been shown to be driven by an endophytic phase to the life cycle, the initial infection of the host being on living leaves. Host specialisation has resulted in high levels of species diversity but within Hymenotorrendiella most of these species remain unnamed. In this paper four species of Hymenotorrendiella are accepted from Eucalyptus in Australia — the leaf-inhabiting H. communis, as well as three wood-inhabiting species, H. clelandii, and two species described here as new, H. spooneri and H. brevis. The leaf-inhabiting H. communis has an endophytic phase to its life cycle, fruiting on dead leaves but with infection initiated while the leaves are still alive and appears to have been moved around the world along with its Eucalyptus host. The biology of the wood-inhabiting species is unknown although H. clelandii occurs also in New Zealand on introduced Eucalyptus. Also described here are two other wood-inhabiting species from New Zealand that are closely related to H. clelandii – H. coriariae from Coriaria arborea, and H. pruinosa from Leptospermum and Kunzea. H. spooneri as accepted here appears to comprise a phylogenetically diverse complex of several closely related sister populations. These populations differ somewhat morphologically, but each is represented by only one specimen, making it impossible at present to assess the possible taxonomic significance of those morphological differences.