UK BAP stipitate hydnoid morphological and molecular taxonomy
RBG Kew, Natural England and Cardiff University are using a combined molecular and morphological approach to resolve the taxonomy of British stipitate hydnoids. These mycorrhizal mushrooms, which have teeth or spines instead of gills, are of conservation concern across Europe and listed as Biodiversity Action Plan species in the UK.
Stipitate hydnoid fungi (Hydnellum spongiosipes is shown) disperse their spores from spines or teeth which project downwards from the fruit body. (Photo: A.M. Ainsworth)
Currently, there are 18 extant stipitate hydnoid species (ectomycorrhizal tooth fungi in the genera Bankera, Hydnellum, Phellodon and Sarcodon) accepted on the British and Irish checklist. These fungi are recognised when fruiting by having spines or teeth under their caps instead of the more familiar mushroom gills. Fifteen of these are currently recognised as UK priority BAP species (of the 76 non-lichenised fungal taxa listed), of which 11 are included on Section 41 of the NERC Act 2006, signifying that they are of principal conservation importance in England. They are all generally regarded as ectomycorrhizal partners of trees in the oak and pine families with respective UK strongholds in the New Forest (mainly with Quercus and Castanea) and Abernethy Forest (mainly with Pinus sylvestris). Across Europe, stipitate hydnoids are regarded as nitrogen-sensitive and fruiting populations are known to have declined significantly due to habitat loss and air pollution (mainly nitrogenous deposition).
Stipitate hydnoids can be recognised as such in the field relatively easily but Identification to species is less straightforward. The fruit bodies darken considerably with age and when wet which can lead to misidentifications and generation of unreliable distribution data. Furthermore, preliminary DNA sequencing results indicate the existence of several undescribed (cryptic) species. To resolve their confused taxonomy, several groups of stipitate hydnoids in the genera Hydnellum, Phellodon and Sarcodon are undergoing further molecular and morphological study. Kew’s input involves sourcing relevant fungal samples from the national collections we hold (the world’s largest fungarium) and from recently collected European material. Morphological taxonomic investigations and some analysis of the results of the combined approach are also carried out at Kew and part-funded by Natural England.
Results of the project are expected to include the description of species new to science which have been discovered in Britain. The taxonomy of stipitate hydnoids in the UK will be clarified thus improving the Checklist of British & Irish Basidiomycota (an ongoing Kew project). This will lead to improvements in identification of these fungi and to reassessments of historic collections and records. In turn these will yield more reliable distribution maps, conservation status assessments and pave the way for ecological studies on their diverse habitat requirements and for appropriate conservation management plans.
It is hoped that the project will also have an impact in a wider European context by harmonising some of the stipitate hydnoid species concepts which currently coexist in different regions of the continent.
Key papers published since 2006
1. Ainsworth, A.M., Parfitt, D., Rogers, H.J. & Boddy, L. (2010). Cryptic taxa within European species of Hydnellum and Phellodon revealed by combined molecular and morphological analysis. Fungal Ecology 3: 65–80.
2. Parfitt D, Ainsworth AM, Simpson D, Rogers HJ & Boddy L. (2007). Molecular and morphological discrimination of stipitate hydnoids in the genera Hydnellum and Phellodon. Mycological Research 111: 761–777.