Logo: to the web site of Uppsala University

The morphological features and chemical compounds found in the first European collection of Calicium victorianum are compared with type material from Australia of C. piperatum F. Wilson. The phylogenetic relationships of the species are discussed by comparing its nuclear rDNA ITS 1-5.8S-ITS2 with that of other species of Calicium.

A molecular dating of the phylogenetically basal eudicots (Ranunculales, Proteales, Sabiales, Buxales and Trochodendrales sensu

Angiosperm Phylogeny Group II) has been performed using several fossils as minimum age constraints. All rbcL sequences available

in GenBank were sampled for the taxa in focus. Dating was performed using penalized likelihood, and results were compared with

nonparametric rate smoothing. Fourteen eudicot fossils, all with a Cretaceous record, were included in this study for age constraints.

Nine of these are assigned to basal eudicots and the remaining five taxa represent core eudicots. Our study shows that the choice of

methods and fossil constraints has a great impact on the age estimates, and that removing one single fossil change the results in the

magnitude of tens of million years. The use of several fossil constraints increase the probability of approaching the true ages. Our

results suggest a rapid diversification during the late Early Cretaceous, with all the lineages of basal eudicots emerging during the

latest part of the Early Cretaceous. The age of Ranunculales was estimated to 120 my, Proteales to 119 my, Sabiales to 118 my,

Buxales to 117 my, and Trochodendrales to 116 my.

A molecular dating of the phylogenetically basal eudicots (Ranunculales, Proteales, Sabiales, Buxales and Trochodendrales sensu APGII) has been performed using several fossils as minimum age constraints. We have sampled all rbcL sequences available in GenBank for the taxa in focus. Dating was done using Penalized Likelihood, and compared with NonParametric Rate Smoothing. We show that choice of method and fossil constraints has a great impact on the age estimates, and that it is important to use several fossil constraints to yield good age estimates. We discuss the 14 fossils we have chosen to include in this study and present a critical review of other fossils potentially useful in dating studies within the basal eudicots. Our results suggest a rapid diversification during the Early-mid Cretaceous, with all the lineages of basal eudicots emerging during the latest part of the Early Cretaceous. The age of Ranunculales was estimated to 120 myr, Proteales to 119 myr, Sabiales to 118 myr, Buxales to 117 myr and Trochodendrales to 116 myr.

Systematic research provides essential evidence for setting conservation priorities for rare and endangered taxa. Phylogenetic analyses can identify cryptic, genetically distinct lineages as well as actively interbreeding, and hence, non-distinctive lineages earlier perceived as separate taxa. A major aim of this study was to identify genetically distinct, rare lineages within two Malvaceae sister-genera, Sidalcea and Eremalche. The focus was two taxon-pairs each consisting of one rare and one more common taxon. The results demonstrate that even within two closely related genera, with a large number of rare taxa, molecular phylogenetic analyses can reveal contrasting degrees of evolutionary divergence and thus contrasting conservation implications for threatened taxa. Contrary to expectations, the substitution rate in the nuclear ribosomal transcribed spacers for annualEremalche did not correspond to the faster evolutionary rate of annuals – compared to perennials – detected earlier within Sidalcea. Branch lengths in the (annual) Eremalche clade were shorter than those of annual members of Sidalcea. The phylogenetic analyses showed that the rare and endangered S. keckii and E. kernensis each are most closely related to a common species that has been regarded as insufficiently distinct to warrant separate taxonomic status. An additional aim of the study was to test the utility of the Phylogenetic Diversity (PD) measure to formalize the procedure of prioritizing conservation efforts. The measure demonstrated S. keckii (but not E. kernensis) to be genetically distinct from its closest relative and a good candidate for conservation. The PD measure was earlier used for assessing conservation priorities for areas, but proved useful to more objectively suggest conservation priorities among threatened taxa. Because this measure is calculated directly from the data, it retains more character information and gives a better representation of genetic diversity than other measures relying on tree topologies.

This thesis deals with the phylogeny of the lichen genus Usnea (Parmeliaceae, Ascomycetes). The relationships and the morphological variation among Usnea species has been studied, as well as the relationship of Usnea to allied genera.

Two species, U. florida and U. subfloridana, which earlier were regarded to form two separate species have been synonymized. In an analysis based on sequence data these two taxa formed a monophyletic group of intermixed specimens. Usnea florida and U. subfloridana have earlier been regarded to form a species pair, but the species pairs concept cannot be applied in this case.

The morphological characters traditionally used for species recognition of a number of European Usnea species have been analyzed regarding their reliability. The evolution and distribution of the morphological characters was studied in relation to a phylogeny based on sequence data. Most characters proved to be homoplastic in relation to the phylogeny. Few characters were consistent in a clade, and the same character could be inconsistent in another clade. Therefore a combination of several characters is recommended for species recognition.

The relationship of Neuropogon to Usnea was investigated based on sequence data. Neuropogon showed to be closely related to Usnea subg. Usnea. The subgenera Eumitria and Dolichousnea formed the sister group to the clade comprising subg. Usnea and Neuropogon. Usnea is paraphyletic in this investigation. Eumitria is treated as a genus and the subgenus Dolichousnea is elevated to generic rank.

The position of Usnea, Neuropogon, Eumitria, and Dolichousnea in the family Parmeliaceae was investigated based on a phylogeny obtained by sequence data. Protousnea probably forms the sister group to the clade of Usnea, Neuropogon, Eumitria, and Dolichousnea. Several monophyletic groups in the family Parmeliaceae were identified.