Research
I am interested in:
1) Fungal taxonomy, phylogenetics and systematics
2) What are the functional differences between different ectomycorrhizal fungi?
Why study Cortinarius?
The genus Cortinarius Fr. contains over 2000 described species and most of them in Europe. Many more are described each year. They occur on every continent except for Antarctica, although they do appear to be cold-adapted. They are mycorrhizal with members of the Fagales, Pinaceae, Dipterocarpaceae, Salicaceae, Ericaceae and Myrtales. Many species are generalists but a few are specific to alder or birch. Thus they are expected to have a great impact on the health and growth of trees. The genus contains a few species which are choice edibles, and a few species that are deadly poisonous. They are poorly understood in the Americas.
Current Research:
Are there selection pressures to evolve a sequestrate form, and if so, what are they?
Sequestrate fungi are fungi whose spores are not forcibly discharged (statismospores) and whose basidia or asci mature inside enclosed, mostly hypogeous (below ground) fruiting bodies or inside only partially exposed (emergent) fruiting bodies. Harry Thiers (in a 1984 paper) hypothesized that there is a selection pressure for statismospory to evolve in arid environments, to increase the humidity in the area where the spores are forming. Bougher and Lebel (2001) hypothesized that fungi growing in very wet environments may evolve the sequestrate state to protect the spore-bearing area (hymenium) from getting too wet. I am going to conduct a study where I look for a correlation between present climate variables and the presence or absence of the sequestrate state, to test these hypotheses. I will look at the dispersion of the two states in a multigene phylogeny of Cortinarius to test whether the evolution of the sequestrate state is random or not.
Past Research:
Cortinarius Species Diversity in British Columbia and Comparison with European Sequences
We sampled 962 Cortinarius specimens from the province of British Columbia, Canada. We present a maximum likelihood tree showing 179 putative Cortinarius species. As a working definition, we considered a “species” to be a monophyletic clade that included a reliably identified reference sequence, with a maximum of 3% ITS sequence variation. If no reference sequence was available, “species” were groups sharing 97% or more sequence identity. By these criteria, 110 putative B.C. species matched European species and 12 B.C. species matched species exclusively found in the Americas. Of the 56 B.C. species that did not match an identified reference sequence, some may be new to science, while others likely represent described species without available sequences. Since the paper has been published, C. parkeri (North America), C. aavae (Europe and North America), C. xanthodryophilus (North America) C. anomalovelatus (North America) and C. barlowensis (North America) have been described. C. phoniceus var. occidentalis has been renamed C. smithii.
Taxonomy and Biogeography of Cortinarius subgenus Cortinarius
Members of this subgenus occur on every continent, except for Africa and Antartica. Cortinarius violaceus is the type species for the genus Cortinarius. C. violaceus occurs with both hardwoods and softwoods. I performed a worldwide taxonomic revision of the subgenus using morphological characters and by building a multigene phylogenetic tree. I described five species: Cortinarius neotropicus, C. palatinus, C. altissimus, C. atrotomentosus, C. carneipallidus. Location and host are useful for delimiting species, as well as micromorphological characters. I used the program BioGeoBears to estimate historical ranges for the group. Australasia was the most probable origin for the group. About 10 million years ago there was a long-distance dispersal event into the neotropics. Since then, numerous speciation events have occurred throughout the neotropics and holarctic regions. This study significantly increased the number of Cortinarius violaceus group species known to occur in the Americas.
