Information derived from Ordovician to Devonian phytodebris is discussed in terms of its utility in phylogenetic; bistratigraphic, paleoecologic and biogeographic studies. Several preparation techniques are described. Studies of latest Ordovician through Early Devonian land plant phytodebris have been important in addressing the origin of early land plants, in making taxonomic distinctions at the species through ordinal levels, and in documenting the phyletic radiation of early land plants