Quillworts are small, spore-bearing, vascular plants, with narrow elongated leaves, which are microphyllous. The leaves contain air chambers that take up carbon dioxide. Leaves are attached in a spiral fashion to a subterranean short corm-like stem. At the base of each leaf below the triangular shaped ligule is found the sporangia. Below the corm-like base are found the roots, which have no vascular tissue. The life cycle is heterosporous similar to that of Selaginella.

New Zealand has only one reported species, which is aquatic. It can be found in some of the North Island lakes but is more common in the lakes of the South Island.