Equisetaceae : Equisetum arvense
Field horsetail tolerates an extremely wide range of soils but prefers more acidic and wet soil conditions with full sunlight. Once established It can grow well in drier places. This species can be an aggressive plant that spreads by branched, creeping rhizomes and tubers. It can be difficult to remove once established due to its very deep rhizomes.
Description
Equisetum arvense is a non-flowering, rhizomatous, perennial herb growing from a rhizome, with dimorphic spreading to ascending stems that grow 10-90 cm in height and dye back each year. The stems are clustered, often forming dense stands. The sterile stems are green and have arching to ascending, whorled branches that are up to 20 cm long. The solid and simple branches have sheaths at the nodes that bear brown to black teeth. The stem is hollow, and the branches are solid. The non-photosynthetic fertile stems are off-white, succulent, 10–25 cm tall, with 4–8 whorls of brown scales and a terminal brown spore cone. The teeth on the fertile stem sheaths are much larger than those on the sterile stems, and the cone is 10–40 mm long and 4–9 mm in diameter. The fertile stems typically appear in early spring. Field horsetail produces short-lived fertile stem in April to June along lakes, streams, in pastures and wooded areas in much of South Dakota.