A perennial member of the horsetail family
A native wetland horsetail with hollow, jointed green stems and spore cones at the tips of fertile shoots.
A mature spore cone above whorled green branches.
Family: Equisetaceae · horsetail family
Genus: Equisetum
Habit: Perennial, colony-forming spore plant
Height: Usually 2–4 feet
Habitat: Shallow water and saturated ground
Spore cones: Late spring and summer
Jointed stems: Upright green shoots have many shallow ridges and a large hollow center.
Toothed sheaths: The tiny leaves form a sleeve around each joint, ending in numerous narrow, dark teeth, commonly 12–24.
Variable branching: Stems may be unbranched or carry whorls of simple, spreading to ascending branches.
Terminal cones: Fertile stems remain green and bear a blunt cone at the tip. The cone opens as it matures and eventually drops away.
Look along muddy shores and in marshes, bogs, swamps and quiet shallow water. Colonies may grow in sun or partial shade.
Young shoots rise in spring. Developing and mature spore cones can be found from late spring into summer.
Native across northern parts of the Northern Hemisphere, including Wisconsin and Illinois. Sightings show reported observations rather than the complete native range.
Field Horsetail (Equisetum arvense) usually produces separate pale fertile shoots before its green branched shoots. Water Horsetail bears cones on green stems.
Marsh Horsetail (Equisetum palustre) also bears cones on green stems, but has fewer sheath teeth and a much smaller central stem cavity. Cone color alone cannot separate these species.
For a closer comparison, examine the stem sheaths and the lowest branch: in Water Horsetail, its first internode is shorter than the adjacent main-stem sheath.
The cone is a spore-producing structure called a strobilus. Its tightly packed units bear spore sacs. As the cone opens, the spores are released; horsetails produce neither flowers nor seeds.
Underground rhizomes also allow established plants to spread into colonies.
