rush-like. Rhizome creeping. Stem aerial, erect, radially symmetrical, and
green with nodes and internodes. Fertile and sterile stems both green or the
fertile ones lacking chlorophyll, Vascular tissue borne adjacent to the cranial
canal, endodermis a continuous ring or separate rings around each vascular
bundle. Nodes with a sheath bearing either persistent or deciduous teeth.
Leaves dry and reduced to teeth of scaly sheath which arise from on internode,
the scaly leaves alternate in position. Strobilus terminal on the main stem or
at the ends of the branches. Sporangia unilocular, borne on the back of the
sporangiophore. Spores spherical, green, homosporous, with 4 elaters.