Karen Hansen

If you were to describe yourself in a maximum of three words – what characterizes you as a person?
Mycologist, fungal biologist, taxonomist

What made you become a scientist? Did you have any role models?
At the University of Copenhagen there was a large number of researcher working on fungal biodiversity, taxonomy, ecology and evolution, when I was a master student and they all influenced me. Besides the one year as a Special Graduate Student at Harvard University Herbaria was extremely inspiring.

What do you find most interesting about your profession?
I simply love to work on fungi.

Fungi are an extremely important, very diverse, but understudied group of eukaryotes that live for a large part hidden in soil, wood, other plant debris, etc. They function as decomposers, symbionts and pathogens. Despite this, so little are still known about fungi, their origin, evolution, diversity and lifestyles.

I like to collect fungi, and study them both in the microscope and at the molecular level, and make the final synthesis from the results, to present it in a paper (written and/or oral).

How did you come to work at the Swedish Museum of Natural History?
The Senior Curator position for fungi was posted and as a post-doc, I was looking for a permanent position, so I applied for the post and got it. The post fitted perfectly for me, with the possibility to continue my research on cup-fungi and work with collections, and also to get back to the Nordic countries after 5 years in the USA. Sweden has a long and important history for fungal taxonomy, from the legacy of Elias Magnus Fries (1794-1878) and the Swedish Museum of Natural History are housing many important fungal collections of especially ascomycetes.

What is your research about?
My research is focused on specimen-based fungal taxonomy and classification. I am interested in the diversity and evolution of fungi/ evolution of their nutritional modes, habitats and morphological features. I use multi-gene phylogenies to study evolutionary relationships and patterns, biodiversity and biogeography. I work on several different taxonomic levels, from species delimitation and relationships, to higher-level classifications, generic, family and order level. For this I conduct fieldwork, molecular phylogenetics and comparative morphological (macro- and microscopically) studies.

I study mainly cup-fungi (the class Pezizomycetes) and more recently also hyaloscyphoid fungi (Hyaloscyphaceae s.l., Helotiales, Leotiomycetes) in collaboration with Seppo Huhtinen and our student Timo Kosonen (Finland).

Name a project or individual work item that you are happy to remember.
I am happy to always have been able to work on cup-fungi that produce very beautiful and often colourful, highly diverse, minute to quite large (0.05-15 cm in diam) disc- or cup-shaped apothecia, but also semi-hypogeous to hypogeous ascomata (truffles). They form the earliest diverging lineage within the Pezizomycotina (the filamentous Ascomycota), and include mainly degraders and ectomycorrhizal symbionts.

What's the biggest surprise you've been through at work?
The result of my PhD work was surprising. I worked on the large, poorly understood, genus Peziza (a genus of cup-fungi) that I collected and studied macro- and micro-morphologically and sampled widely for molecular phylogenetic analyses. My results identified 14 fine-scale lineages within Pezizaceae and showed that species of Peziza occur in eight of the lineages, spread among other genera of the family. These new lineages were (to a large extent) supported by macro- and micro-morphological features, e.g. distinct types of ascus amyloid reactions, spore surface relief, guttulation, excipulum structure and pigments; anamorphic type; and ecological features, degraders versus symbionts.

There has been many big surprises working on cup-fungi: just to go collecting in Sweden and you find a species with such a combination of morphological characters that you have never seen before and that has never been described, and perhaps even does not fit into any genus previously described.

What do you want to achieve with your research, individually or together with others?
Together with my collaborators, I want to contribute to explore, unravel and document the diversity of fungi, infer their evolutionary relationships and geographic distribution. At the same time, search for new characters to resolve and describe taxa, and for understanding their origin and evolution.

What do you like to do in your spare time?
I like to work on fungi even in my spare time. I like to take walks and swim, talk to family, friends and colleagues.