CONTENS - International Organization of Plant Biosystematists

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Evolving towards the tops: phylogeny and evolution of the
European endemic Phyteuma (Campanulaceae)
Gerald M. Schneeweiss 1 , Michael Barfuss 2 , Mike Thiv 3
1 Department of Biogeography and Botanical Garden, University of Vienna, Rennweg
14, A-103 Vienna
2 Department of Systematic and Evolutionary Botany, University of Vienna, Rennweg
14, A-103 Vienna
3 Department of Botany, Federal Natural History Museum Stuttgart, Rosenstein 1, D-
70191 Stuttgart
Phyteuma comprises c. 20 species endemic to Europe and is morphologically
characterized by its peculiar flower morphology with long and narrow corolla lobes
remaining attached distally and separating only late in anthesis. Phyteuma species
occur in different habitats, ranging from lowland woodlands via mid-elevation rock
crevices to alpine grasslands and subnival tundra, rendering it a good model system
to investigate habitat evolution in a comprehensive phylogenetic context. To this end,
we established a sound hypothesis on the relationships among all Phyteuma species
based on phylogenetic analysis of 4.3 kb sequence data from the plastid (trnL-intron
and trnL-trnF spacer, trnK-intron including the matK gene) and the nuclear genome
(ITS). Phyteuma is a well supported monophyletic group and is sister to the SE
Alpine endemic Physoplexis. Within Phyteuma, two clades are found, largely
corresponding to previously recognized sections, which were delimited by the
distribution of different inflorescence types (spikes vs. capitulae). The majority of
currently recognized species are confirmed as separate lineages, while in others,
most notably Ph. globulariifolium and Ph. scheuchzeri, current taxonomy does not
adequately reflect lineage diversity. Using this phylogenetic framework, habitat
evolution is analyzed under the assumptions that habitat evolution correlates either
with the amount of molecular evolution (phylogram branch lengths) or with time
(branch length of an ultrametric tree). Although the morphologically more primitive
taxa occur in woodlands, there is no evidence that this habitat was the ancestral one
for the genus, but rather the ancestor of Phyteuma was a chasmophyte,
alpine/subnival habitats being clearly derived.
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