Rhymokalon, a new plant with cladoxylalean anatomy from the Upper Devonian of New York State

Rhymokalon trichium, gen. et sp. nov., is a new plant with cladoxylalean anatomy from Upper Devonian rocks (Oneonta Formation) of New York. The new plant consists of three orders of helically arranged branches. Compressed axes have numerous longitudinal ridges, which are interpreted as resulting from the collapse of external tissues onto the dissected xylem during compaction of the sediment. Distal branchings bear small numbers of fine hairs. Petrified basal branches contain a multiribbed stele, from which are produced numerous xylem strands which enter the branches. Lateral branches have many xylem strands, which divide and anastomose freely. This type of anatomy relates Rhymokalon best with Cladoxylales, a group of Devonian and Carboniferous plants with dissected xylem.