Phylogenetic and ecological studies in lichenology : including studies of both mycobiont and photobiont

Sammanfattning: In this thesis different aspects in lichens are investigated, namely, the phylogeny of mycobiont and photobiont, and ecology in the form of species richness of certain habitats of the Uppland province, Sweden.Analyses of ITS sequences of the lichenized fungi genus Roccella (Roccellaceae) provide an intrageneric topology of the genus with emphasis on the European, Mediterranean and Macaronesian species. One species, Roccella elisabethae Tehler, is described and a key to the Macaronesian and European species is provided. Sequences from five Roccella species are new. One significant result is that the Macaronesian species constitute a monophyletic group.Newly designed algal-specific primers were used to amplify the ribosomal ITS region from 25 photobiont specimens from five lichenized fungal species of the family Physciaceae (Lecanorales). Trebouxia impressa was present in all mycobionts except Anaptychia ciliaris, which instead was associated with Trebouxia arboricola. A phylogeny for the photobiont, T. impressa, was compared to a phylogeny of the corresponding mycobionts. The general similarity of the mycobiont and photobiont trees may indicate a coevolutionary history. The ribosomal SSU region and the rbcL gene were sequenced from total DNA extracts from thalli of 8 species of Siphula (Icmadophilaceae) and 6 species of Parasiphula (Coccotremataceae). All specimens were found to have Elliptochloris bilobata in a wider sense as photobiont, indicating independent accession of photobionts for the two mycobiont genera.The epiphytic lichen flora on Fraxinus exelcior and Acer platanoides in lanes and two types of wooded meadows were investigated in Uppland, Sweden. Altogether 129 lichen species were found, five of which are listed in the Swedish Red List of threatened species. The species richness was affected by substrate, habitat, and distance to dust source. Lanes had the highest species richness, and Fraxinus excelsior had higher species richness than Acer platanoides.