Inferring the Root of Isoëtes: Exploring Alternatives in the Absence of an Acceptable Outgroup.

The article reports on the results of a study of the phylogenetic root of the lycopsid genus, Isoëtes. The study examined the characteristics of the early branching patterns within Isoëtes using an expanded set of taxa and three molecular markers. It also assessed the saturation in the molecular data sets, tested for differences in evolutionary rate, determined the stability of the ingroup topology and evaluated the applicability of the molecular clock.