Wednesday 9 April 2014

Swedish Hawkweeds: Scandi jaune?

The April issue of New Journal of Botany is now at the printers and here is another sneak preview: we are delighted to publish a paper by Dr Torbjörn Tyler of University of Lund, Sweden on 'Critical notes on species of Hieracium (Asteraceae) reported as common to Sweden and Britain'. Torbjörn is responsible for the project The Hieracia of Sweden, is Curator of the Herbarium at Lund LD and is also Editor in Chief of Nordic Journal of Botany. I asked him to tell us something about his work and he said "Although people may believe differently when looking at my list of publications, my main interest is plant biogeography". [Follow the link to read Torbjörn's clear definition of this term.]

Torbjörn in the field
By kind permission, T. Tyler
He continued "When working with the geographic distribution of genetic variation within widespread woodland species for my PhD, using the relatively poor molecular markers available in those days, I recognized the potential of apomictic clones/taxa as ‘markers’ in biogeographical analyses. Therefore, I made a first attempt to analyse the known distributions of the 1,000+ species of Hieracium in Sweden recognized by early C20th experts. However, I found that the available distribution data as summarised by these authors was too coarse to answer my questions about how these relatively recently-evolved taxa have spread in our post-glacial landscape.

"In addition, I recognised that the patterns observed might be difficult to interpret convincingly as long as there is no consensus about how, when and where these taxa have evolved. Further, I found that it was a great pity that virtually no work had been done on Hieracium in Scandinavia since the 1940s. So in 1997 I began to revise the old literature and all existing herbarium material of Hieracium, beginning with the relatively species-poor southernmost Swedish provinces and when I later got the opportunity to also do molecular and cytological analyses, I tried to use these techniques, in combination with thorough multivariate morphometric analyses, to get a better understanding of the evolutionary history and relationships of the species. 

Tim Rich, British Hieraciologist, with a Taraxacum!
Image: C. Gait
"Since then, I have revised all species of H. sectt. Hieracium, Vulgata, Bifida and Oreadea in southern Sweden and in the northern Baltic provinces. Only the species from the northern inland provinces remain, but these also present the largest problems since these remote regions were barely accessible to the early C20th experts, and many taxa growing there remain undescribed. In this work, I have had invaluable help from numerous local amateur botanists, who have made valuable new collections from their home provinces and sometimes also managed to learn their species, strengthening me in my hope that the revisions and keys I have published may indeed be of some use. In addition, I have gained some colleagues who have started to work with those sections of the genus that I considered to be outside my own scope, e.g. H. sectt. Tridentata and Foliosa.

Pilosella officinarum Mouse-ear hawkweed
Image: C. Ferguson-Smyth
"Although most Hieracium species are certainly regional or national endemics that have evolved in post-glacial times, a few species have confirmed wider distributions and, for many more, dubious far disjunct records are reported in the literature. It is in this context that my forthcoming paper for New Journal of Botany, on the identity of some British Hieracium species, came into being.

"Thus, since all biogeographic research depends on the accurate identification of the biological entities studied, I have become increasingly involved in purely taxonomic research, not only in Hieracium but also in several groups of e.g. introduced and potentially invasive species whose origin and taxonomy is not well understood. Furthermore, I consider knowledge of biogeographic facts and processes as the key to biological conservation and I have accordingly taken active part in many nature conservation issues and projects trying to assess recent and ongoing changes in the Swedish flora and its underlying causes".

Many thanks to Torbjörn for telling us about his work and his forthcoming paper for New Journal of Botany. Did you know that Lund was the first university attended by Carl Linnaeus?And I hope you like the Pilosella - another yellow Comp! - which Claudia has selected as the second of her images to appear on the cover of the April issue. 

No comments:

Post a Comment

Please leave a comment!