Over the last several years, the phylogeny of land plants and its various associated issues have been investigated using analyses of single to multiple genes with different extent of taxon sampling, morphological data, and organellar genomic structural characters. At present, the following issues remain contentious: the first lineage of land plants, the sister lineage of vascular plants, relationships among Equisetum, Psilotaceae, eusporangiate and leptosporangiate ferns, monophyly of extant gymnosperms, and the exact position of Gnetales. Here we analyze a data set of four mitochondrial (atp1 and LSU rDNA), plastid (rbcL), and nuclear (18S rDNA) genes from 150 species of land plants. We explore the effectiveness of this broad, moderately dense taxon and character sampling strategy in reconstructing the land plant phylogeny. The random outgroup rooting strategy was employed to evaluate validity of charophytes as an outgrup to land plants. We also examine substitution rates of these genes across land plants and use the sequence data to estimate divergence times of land plants as well as its various component clades.

Key words: land plant phylogeny, multigene analysis