Abstract.-
Because of the fragmentary preservation of the earliest Cooksonia-like terrestrial plant macrofossils, younger Devonian fossils with complete anatomical preservation and documented gametophytes often have received greater attention concerning the early evolution of vascular plants and the alternation of generations. Despite preservational deficits, however, possible physiologies of Cooksonia-like fossils can be constrained by considering the overall axis size in conjunction with the potential range of cell types and sizes, because their lack of organ differentiation requires that all plant functions be performed by the same axis. Once desiccation resistance, support, and ...