Common Horsetail, Field Horsetail: Equisetum arvense -

Ferriss' Horsetail: Equisetum xferrissii (Synonym: Equisetum hyemale var. elatum) -

Swamp Horsetail, River Horsetail, Water Horsetail: Equisetum fluviatile (Synonym: Equisetum limosum) -

Hybrid Horsetail: Equisetum xfont-queri -

Common Scouring-rush, Common Scouring-rush, Scouring-rush Horsetail, Dutch Rush, Prairie Scouring-rush: Equisetum hyemale var. affine -

Smooth Scouring Rush: Equisetum laevigatum (Synonyms: Equisetum funstonii, Equisetum kansanum) -

Litorale Horsetail: Equisetum xlitorale -

Marsh Horsetail: Equisetum palustre -

Giant Horsetail, Great Horsetail: Equisetum telmateia var. braunii (Synonym: Equisetum maximum) -