Selaginella - phylogeny of the South American species within subgenus Stachygynandrum

Abstract: Selaginellaceae is a family within the lycophytes, and it comprises one genus, Selaginella. They are herbaceous seedless vascular plants found globally, with around 750 species. Selaginella is divided into several subgenera, but there is no classification that is agreed upon. This thesis is based on one of these classifications (Weststrand & Korall, 2016a,b). The subgenus Stachygynandrum is the most species rich from that study. Within the subgenus is an unresolved clade of South American species. The aim of this study is to contribute to resolve the phylogeny of that clade. A phylogenetic analysis using Bayesian inference was used on the chloroplast regions atpB, rbcL-atpB intergenic spacer and psbE-petL intergenic spacer. These have previously never been used for studies on the Selaginella phylogeny. New primers were constructed for these regions. The datasets from all three regions were also concatenated. This study’s data was also combined with data from Weststrand and Korall (2016b). There were successful amplifications of all new regions, but most specimens failed to be amplified. The phylogenies from the new three regions are mostly in agreement with the one presented by Weststrand & Korall (2016b). The clade splits into two larger groups. Some branch support differ between this study and the previous study. The position of S. huehuetenangensis was resolved in this study as a sister group to S. reflexa and S. apoda, with a posterior probability of 1. Two specimens identified as S. umbrosa are on different branches in the tree.