| Common Name | Scientific Name | Code |
| n/a | Equisetum ?dycei C.N. Page [excluded] | EQDY2 |
| n/a | Equisetum ?ferrissii Clute (pro sp.) [hyemale ? laevigatum] | EQFE |
| n/a | Equisetum ?litorale K?hlewein ex Rupr. (pro sp.) [arvense ? fluviatile] | EQLI |
| n/a | Equisetum ?mackaii (Newm.) Brichan [hyemale ? variegatum] | EQMA |
| n/a | Equisetum ?nelsonii (A.A. Eat.) Schaffn. (pro sp.) [laevigatum ? variegatum] | EQNE |
| Alaskan scouringrush | Equisetum variegatum Schleich. ex F. Weber & D.M.H. Mohr var. alaskanum A.A. Eat. | EQVAA |
| branched scouringrush | Equisetum ramosissimum Desf. | EQRA |
| dwarf scouringrush | Equisetum scirpoides Michx. | EQSC |
| Equisetum ?ferrissii | Equisetum hyemale L. var. elatum (Engelm.) Morton | EQHYE |
| Equisetum ?ferrissii | Equisetum hyemale L. var. intermedium A.A. Eat. | EQHYI |
| Equisetum ?ferrissii | Equisetum intermedium (A.A. Eat.) Rydb. | EQIN |
| Equisetum ?mackaii | Equisetum trachyodon (A. Braun) W.D.J. Koch | EQTR |
| Equisetum ?mackaii | Equisetum variegatum Schleich. ex F. Weber & D.M.H. Mohr var. jesupii A.A. Eat. | EQVAJ |
| Equisetum ?nelsonii | Equisetum variegatum Schleich. ex F. Weber & D.M.H. Mohr var. nelsonii A.A. Eat. | EQVAN |
| Equisetum arvense | Equisetum arvense L. var. alpestre Wahlenb. | EQARA |
| Equisetum arvense | Equisetum arvense L. var. boreale (Bong.) Rupr. | EQARB |
| Equisetum arvense | Equisetum arvense L. var. campestre Wahlenb. | EQARC |
| Equisetum arvense | Equisetum arvense L. var. riparium Farw. | EQARR |
| Equisetum arvense | Equisetum calderi Boivin | EQCA |
| Equisetum fluviatile | Equisetum fluviatile L. var. limosum (L.) Gilbert | EQFLL |
| Equisetum fluviatile | Equisetum limosum L. | EQLI3 |
| Equisetum hyemale var. affine | Equisetum affine Engelm. | EQAF |
| Equisetum hyemale var. affine | Equisetum hyemale L. ssp. affine (Engelm.) Calder & Taylor | EQHYA2 |
| Equisetum hyemale var. affine | Equisetum hyemale L. var. californicum Milde | EQHYC |
| Equisetum hyemale var. affine | Equisetum hyemale L. var. pseudohyemale (Farw.) Morton | EQHYP |
| Equisetum hyemale var. affine | Equisetum hyemale L. var. robustum (A. Braun) A.A. Eat. | EQHYR |
| Equisetum hyemale var. affine | Equisetum praealtum Raf. | EQPR3 |
| Equisetum hyemale var. affine | Equisetum robustum A. Braun | EQRO |
| Equisetum hyemale var. affine | Hippochaete hyemalis (L.) Bruhin | HIHY2 |
| Equisetum hyemale var. affine | Hippochaete hyemalis (L.) Bruhin ssp. affinis (Engelm.) W.A. Weber | HIHYA |
| Equisetum laevigatum | Equisetum funstonii A.A. Eat. | EQFU2 |
| Equisetum laevigatum | Equisetum kansanum Schaffn. | EQKA2 |
| Equisetum laevigatum | Equisetum laevigatum A. Braun ssp. funstonii (A.A. Eat.) Hartman | EQLAF |
| Equisetum laevigatum | Hippochaete laevigata (A. Braun) Farw. | HILA5 |
| Equisetum palustre | Equisetum palustre L. var. americanum Victorin | EQPAA |
| Equisetum palustre | Equisetum palustre L. var. simplicissimum A. Braun | EQPAS |
| Equisetum sylvaticum | Equisetum sylvaticum L. var. multiramosum (Fern.) Wherry | EQSYM |
| Equisetum sylvaticum | Equisetum sylvaticum L. var. pauciramosum Milde | EQSYP |
| Equisetum telmateia var. braunii | Equisetum braunii Milde | EQBR |
| Equisetum telmateia var. braunii | Equisetum maximum auct. non Lam. [misapplied] | EQMA2 |
| Equisetum telmateia var. braunii | Equisetum telmateia Ehrh. ssp. braunii (Milde) Hauke | EQTEB2 |
| Equisetum variegatum var. alaskanum | Equisetum variegatum Schleich. ex F. Weber & D.M.H. Mohr ssp. alaskanum (A.A. Eat.) Hult | EQVAA2 |
| Equisetum variegatum var. variegatum | Equisetum variegatum Schleich. ex F. Weber & D.M.H. Mohr var. anceps Milde | EQVAA3 |
| Equisetum variegatum var. variegatum | Hippochaete variegata (Schleich. ex F. Weber & D.M.H. Mohr) Bruhin | HIVA |
| field horsetail | Equisetum arvense L. | EQAR |
| giant horsetail | Equisetum giganteum L. | EQGI |
| giant horsetail | Equisetum telmateia Ehrh. | EQTE |
| giant horsetail | Equisetum telmateia Ehrh. var. braunii (Milde) Milde | EQTEB |
| horsetail | Equisetum L. | EQUIS |
| marsh horsetail | Equisetum palustre L. | EQPA |
| meadow horsetail | Equisetum pratense Ehrh. | EQPR |
| scouringrush horsetail | Equisetum hyemale L. | EQHY |
| scouringrush horsetail | Equisetum hyemale L. var. affine (Engelm.) A.A. Eat. | EQHYA |
| smooth horsetail | Equisetum laevigatum A. Braun | EQLA |
| variegated scouringrush | Equisetum variegatum Schleich. ex F. Weber & D.M.H. Mohr | EQVA |
| variegated scouringrush | Equisetum variegatum Schleich. ex F. Weber & D.M.H. Mohr var. variegatum | EQVAV |
| water horsetail | Equisetum fluviatile L. | EQFL |
| woodland horsetail | Equisetum sylvaticum L. | EQSY |