CITATIONS SEE PROFILE

to identify. At the specific level, however, this is quite another matter and the to be e be con ni-tion ly iden ld trip us any T tly prev he taxo ea has m gen be brie The ly con ng *Con nd. 0024taxonomy of Usnea is considered by most modern lichenologists xceptionally diYcult, where most of the described species seem to nected by a continuous array of transitional forms, impeding the recog of well-defined species. Most of the herbarium material is wrong tified or labelled just as Usnea sp. It has come to the point that on fie s some lichenologists do not even want to collect specimens of this gen more. he purpose of this paper is to discuss the modern species concept curren ailing, together with the characters that are commonly employed in t nomy of this genus. On this basis, I will try to explain why the genus Usn such a bad taxonomic reputation. Josef Motyka’s monograph ‘ Lichenu eris Usnea studium monographicum ’, and his species concept, will fly analysed. What is a Species? re is no general agreement on this question today and the issue is high troversial. The biological species concept that defines species as be