Reevaluation of the species of Hieracium sect. Hieracium that were described by Hylander from introduced populations in Scandinavian parks

Hylander treated 144 species of Hieracium sect. Hieracium found in Scandinavian parks, 132 of which were described for the first time. However, he did not supply any determination key, only a few species were illustrated and hints about the differences between species were few. In addition, the species concept of Hylander was obviously much narrower than what has been agreed upon by those working with native Scandinavian species of this group. The species treated have all been introduced to northern Europe, presumably from Southern Germany or France, during the latter half of the 19th century as contamination of commercial grass-seed, but the majority of the species is still not known from any native occurrences. In the present paper, all these "park-Hieracia" are described in a standardized manner, and illustrations as well as a determination key to all species are provided. The types are indicated for all species and six taxa are lectotypified. The number of species have been reduced to 95 by merging those species that were found to be identical Or unacceptably closely similar. A way of constructing a numerical description taking into consideration 33 different characters is described. The numerical description was used to calculate an overall similarity index for all pairs of species and thereby identify synonymous names. In addition, the numerical description was found to be of great help when constructing the determination key