Equisetum hyemale L.

Plants large. Rhizome creeping or erect, blackish brown, nodes and roots with long yellowish brown trichomes. Aerial stem perennial, monomorphic, green, up to or more than 1 m tall, (3-)5-9 mm in diam. at middle, not branched or base with few erect lateral branches; internodes 5-8 cm. Aerial stem 16-22-ridged; ridges arc-shaped abaxially or nearly rectangular, without conspicuous tubercles or with 2 rows of tubercles; sheath 0.7-1.1 cm, blackish brown or both distal portion and base with a blackish brown band, or only distal portion with a blackish brown band; sheath teeth 16-22, lanceolate, small, 0.3-0.5 cm, teeth of distal portion light brown, membranous, aristate, caducous, teeth of lower portion blackish brown, abaxially 3-or 4-ridged at base, thinly leathery, persistent or falling off early with sheath tube. Strobilus ovate, 1-1.6 cm, 0.4-0.7 cm in diam., apex with small acute tip, sessile. 2n = 216.

It is a temperate plant. It grows in cool climates. It grows in moist soil and up to 20 cm of water. In N China it grows along the banks of streams between 100-3,000 m above sea level. It suits hardiness zones 3-10.

CAUTION: It should not be used in large amounts nor used for long periods of time. The leaves are boiled to make a drink. The stalk tops are dried then mashed and mixed with other foods. The dried rootstocks are used as a famine food.

It can be grown by dividing the underground stem or rhizome. It can be grown by spores but this is difficult.