Mats H. G. Gustafsson

In an attempt to improve the phylogenetic resolution in clades of the genus Blumea beyond what could be achieved with sequence data from plastid regions ( trnL­F, psbA­trnH ) and ITS, the 5S­NTS (non­transcribed spacer) was sequenced as it has been reported to show higher levels of variation than the former regions. 5SNTS yields a tree less resolved than ITS and the plastid regions; the latter markers, moreover, provided more resolution at deeper nodes. When combined with ITS and plastid sequences, 5S­NTS adds very little resolution. The results indicate that previously published, morphology­based sectional classifications of the genus are highly unnatural. The three varieties of B. hieraciifolia belong to different clades and should be treated as different species.

The taxonomically poorly known, neotropical genus Clusia (Clusiaceae) comprises over 300 species of trees, shrubs and hemiepiphytes. The flowers are morphologically highly diverse and offer either nectar, pollen or resin as a reward for pollinators. Resin production in flowers is a poorly studied phenomenon, known from only five angiosperm genera. Variation in sequences of the nuclear ribosomal ITS region was analysed cladistically in order to trace the evolution of floral resin production in Clusia , and as a first step towards a phylogenetically based reclassification of the genus. The most parsimonious trees show that the genera Havetia, Havetiopsis, Oedematopus and Quapoya are nested inside Clusia. Traditionally, Clusia has been divided into sections based on androecial variation, and most of these groups are supported as monophyletic based on the ITS data. Sections Retinostemon, Havetia and Cochlanthera together form one of very few well‐supported suprasectional groups. Character optimisation experiments suggest that resiniferous flowers have evolved at least three times independently in Clusia , but a character‐evolution model with a single origin for floral resin is only slightly less parsimonious. Clades of resiniferous species are morphologically the most diverse, and it is concluded that resin production has been a key innovation triggering floral morphological diversification. Secondary losses of resin and switches to apomixis seem to be correlated with colonisation of habitats and areas where resin‐collecting bees are less frequent.

The small but morphologically diverse subfamily Barnadesioideae of the sunflower family, Asteraceae, is of special interest as it constitutes the sister‐group to the rest of the family. Therefore it is of critical importance for elucidating the origin and early evolution of Asteraceae. Cladistic analyses of DNA sequence variation in the trnL intron and nuclear ribosomal ITS regions strongly support five major clades in the subfamily: Schlechtendalia, Chuquiraga‐Doniophyton, Barnadesia‐Huarpea, Dasyphyllum subgenus Dasyphyllutn and a clade comprising Dasyphyllum subgenus Archidasyphyllum, Arnaldoa and Fulcaldea. Within Dasyphyllum subgenus Dasyphyllum, D. hystrix has a basal position, and sect. Macrocephala is supported as monophyletic, while sect. Microcephala lacks jackknife support. Within Barnadesia, B. parviflora has a very divergent ITS sequence and a basal position in the genus. The phylogenetic trees make some sense of the great morphological variation within the subfamily, although some clades identified here lack obvious defining morphological characteristics. Optimisation of geographical distributions onto the molecular phylogenies shows that the Barnadesioideae most likely originated in southern South America.