‘Early wood’ samples reshape plant history

BBC : Woody plants probably appeared earlier than previously thought. Phillipe Gerrienne of the University of Liege, Belgium, and colleagues made a study of plants from the Early Devonian age, about 10 million years before the widespread appearance of shrubs and trees, and found rings of cells that are characteristic of wood. Rather than to provide structural support, that woody substance may have been used to enhance the flow of water in plants. While some early ferns produced some wood, they didn’t show the characteristic pattern of cell division perpendicular to the stem typical of lignophytes. The plants in the study, which were herbaceous and probably no more than 20–40 cm tall, would not necessarily have been distinguishable externally from nonwoody plants.