[Equisetum arvense f. macrostachya A. A. Eat., moreEquisetum arvense f. microstachya A. A. Eat., Equisetum arvense subsp. alpestre (Wahlenb.) Schönsw. & Elven, Equisetum arvense subsp. boreale (Bong.) Tolm., Equisetum arvense var. diffusum A. A. Eat., Equisetum arvense var. granulatum G. Lawson, Equisetum arvense var. polystachyon A. A. Eat.]
Infrequent to frequent throughout the state. Where it is found it usually forms large colonies, especially in its preferred habitat along railroad embankments. It prefers a moist, sandy soil, usually lean in organic matter, but it is also found in moist places on the borders of bogs and along streams. It grows in both shade and sun and its appearance is so erratic and it is so widespread that I am not able to tell what controls its distribution. Once I saw where it had almost covered a sandy fallow field in the valley of Pigeon River. The plant is extremely variable and many varieties have been named, several of which have been reported from Indiana. According to Schaffner these variations are all ecological and not worth recognition.