- Small or medium-sized ferns, native, wet or shallow aquatic. Rhizomes are long and horizontal, black, branched, noded, rooting at nodes, tomentose. The branches above the ground are upright, cylindrical, green, knotted, hollow and cavity. The epidermis often has siliceous nodules, solitary or verticillate branches on nodes; there are longitudinal ridges and grooves between nodes. Leaf scales, whorled, confluent into a tube at each node
- Asked by Subgen. Subset. Equisetum
Subgenus Subgen. Hippochaete (Milde) Baker
- E. hyemale
- Large plants. Rhizomes are lateral or erect, dark brown, nodes and roots with yellow-brown hairs. Ground branches perennial. Stick type. Up to 1 meter or more, middle (3) 5-9 mm in diameter, internodes 5-8 cm long, green, unbranched or with few upright side branches at base. Above ground branches have 16-22 ridges, the back of the ridge is curved or nearly square, no obvious nodules or 2 rows of nodules; sheath tube 0.7-1.0 cm, black brown or one circle at the top and one at the base or only one at the top Black-brown; sheath teeth 16-22, lanceolate, small, 0.3-0.4 cm long. The apex is light brown, membranous, awn-like, early-falling, and the lower part is black-brown, thin-leathery. The back of the base has 3-4 longitudinal edges, which persist or fall early with the sheath tube. The sporangia are ovate, 1.0-1.5 cm long, 0.5-0.7 cm in diameter, with small spikes at the apex, sessile.


