Figure 1

Combined Zygnematophyceae and Spirogyra SSU rRNA phylogeny: Molecular phylogeny of Desmidiaceae, Peniaceae, Closteriaceae, Mesotaeniaceae and Zygnemataceae based on SSU alignment. The phylogenetic tree was inferred by maximum likelihood analyses of 1720 aligned positions of 33 taxa using PAUP* 4.0b10. TrN+G+I was chosen as best evolutionary model (base frequencies: A 0.25, C 0.23, G 0.27, T 0.25; rate matrix: A-C 1.0000, A-G 1.8721, A-T 1.0000, C-G 1.0000, C-T 4.5252, G-T 1.0000) with the proportion of invariable sites (I= 0.4608) and gamma distribution parameter (G= 0.6376). Posterior Probabilities (>95%; bold; calculated by MrBayes 3.1.2 using the covariation settings (3 million generations, trees from 4100 – 30000)) as well as bootstrap values (>50%) of the maximum likelihood (100 replicates; bold italic), neighbor-joining (1000 replicates; italic), and maximum parsimony (1000 replicates; not bold) are given in the tree (PP/ML/NJ/MP). No outgroup was used. ATT4, 5, 7 and 8 refer to alternative tree topologies tested with consel – please refer to Table 1 for details. Figure 1a: upper right corner: Combined Zygnematophyceae and Spirogyra SSU rRNA phylogeny (same as Figure 1) using 2 taxa as outgroup; numbers in brackets indicate number of taxa included in groups.