Equisetaceae: Equisetum arvense
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Family Name
Equisetaceae
Common Name
Equisetum arvense
Native American Name
Lakota: waŋyéča swúla, pȟeží swúla
Description
Equisetum arvense is a perennial, herbaceous vascular plant belonging to the family Equisetaceae. It has a complex root system composed of extensive rhizomes that facilitate vigorous asexual reproduction and spread. The plant produces separate fertile and sterile shoots. Sterile stems are green, photosynthetic, hollow, jointed, and rough-textured due to silica deposits; they are branched or unbranched, typically 30–60 cm tall. Fertile stems appear earlier, are unbranched, pale tan to brownish, and bear spores in cone-like sporangia (strobili) at their tips, 5–10 cm long. Leaves are reduced to small scales fused into sheaths at the stem joints. The plant reproduces via spores rather than seeds. Fertile shoots emerge in early spring, and sterile shoots develop afterward. Spores are produced in spring, and the plant continues vegetative growth throughout the growing season. Field horsetail is native to South Dakota, found in moist to wet habitats such as riverbanks, ditches, wet meadows, and disturbed wetlands, with broad statewide distribution.
Horticulture Notes
Spore Collection: Collect fertile stalks when cones are mature but before spores disperse, usually in spring.
Germination: Spores require moist, shaded conditions for germination; vegetative reproduction via rhizomes is the primary method of spread. Spores produce small gametophyte plants in a couple of months. These plants generate sporophytes (spore producing) plants later in the year or in the following year.
Vegetative Propagation: Easily spreads by underground rhizomes; division of rhizome clumps is common for propagation.
Soils: Prefers moist, poorly drained to saturated soils, including clay, silt, and organic-rich substrates.
Light: Tolerates full sun to partial shade.
Water: Requires wet to saturated soils; tolerates standing water and fluctuating hydrology.
Additional Notes
Field horsetail is native and historically used by Indigenous peoples and herbalists for medicinal purposes, including treatments for urinary tract issues, wounds, and as a diuretic. It contains high silica content that can be toxic if consumed in large amounts or improperly prepared due to thiaminase enzymes. It provides important ground cover and habitat in wetland areas but can become invasive in some settings.