• Asteroxylon mackia Kidston & Lang †
• Baragwanathia longifolia Lang & Cookson, 1935 †
• Baragwanathia subulifolia †
• Bergeria quadrata †
• Calamaria saccharata (Engelm.) Kuntze accepted as Isoetes saccharata Engelm.
• Diphasiastrum alpinum (L.) Holub accepted as Lycopodium alpinum Linnaeus
• Diphasiastrum complanatum (L.) Holub accepted as Lycopodium complanatum Linnaeus
• Diphasiastrum digitatum (Dill. ex A. Braun) Holub accepted as Lycopodium digitatum Dill. ex A. Braun
• Diphasiastrum habereri (House) Holub accepted as Lycopodium habereri House
• Diphasiastrum issleri (Rouy) Holub accepted as Lycopodium issleri (Rouy) Domin
• Diphasiastrum sabinifolium (Willd.) Holub accepted as Lycopodium sabinifolium Willd.
• Diphasiastrum sitchense (Rupr.) Holub accepted as Lycopodium sitchense Rupr.
• Diphasiastrum tristachyum (Pursh) Holub accepted as Lycopodium tristachyum Pursh
• Diphasiastrum zeilleri (Rouy) Holub accepted as Lycopodium zeilleri (Rouy) Greuter & Burdet
• Diphasium alpinum (L.) Rothm. accepted as Lycopodium alpinum Linnaeus
• Diphasium anceps (Wallr.) A. & D. Löve accepted as Lycopodium complanatum Linnaeus
• Diphasium chamicyparissus (A. Braun) A. & D. Löve accepted as Lycopodium tristachyum Pursh
• Diphasium complanatum (L.) Rothm. accepted as Lycopodium complanatum Linnaeus
• Diphasium issleri (Rouy) Holub accepted as Lycopodium issleri (Rouy) Domin
• Diphasium sitchense (Rupr.) A. & D. Löve accepted as Lycopodium sitchense Rupr.
• Diphasium tristachyum (Pursh) Rothm. accepted as Lycopodium tristachyum Pursh
• Diphasium wallrothii H.P. Fuchs accepted as Lycopodium complanatum Linnaeus
• Diphasium zeilleri (Rouy) Damboldt accepted as Lycopodium zeilleri (Rouy) Greuter & Burdet
• Haplostigma lenticularis O. Barbosa †
• Huperzia acerosa (Sw.) Holub
• Huperzia appalachiana Beitel & Mickel
• Huperzia aqualupiana (Spring) Rothm.
• Huperzia bartleyi (Cusick) Kartesz & Gandhi
• Huperzia buttersii (Abbe) Kartesz & Gandhi
• Huperzia chinensis (Christ) Czern.
• Huperzia dichotoma (Jacq.) Trevisan
• Huperzia erubescens (Brack.) Holub
• Huperzia filiformis (Sw.) Holub
• Huperzia funiformis (Cham. ex Spring) Trevisan
• Huperzia haleakalae (Brack.) Holub
• Huperzia helleri (Herter) Kartesz & Gandhi
• Huperzia hippuridea (H. Christ) Holub
• Huperzia linifolia (L.) Trevisan
• Huperzia lucidula (Michx.) Trevisan
• Huperzia mannii (Hbd.) Kartesz & Gandhi
• Huperzia miyoshiana (Makino) Ching accepted as Huperzia chinensis (Christ) Czern.
• Huperzia montana (Underw. & F.E. Lloyd) Holub
• Huperzia nutans (Brack.) Rothm.
• Huperzia occidentalis (Clute) Kartesz & Gandhi
• Huperzia phyllantha (Hook. & Arn.) Holub
• Huperzia pithyoides (Schltdl. & Cham.) Holub
• Huperzia polytrichoides (Kaulfuss) Trevisan
• Huperzia porophila (Lloyd & Underwood) Holub
• Huperzia reflexa (Lam.) Trevisan
• Huperzia selago (L.) Bernh.
• Huperzia serrata (Thunb. ex Murr.) Trevisan
• Huperzia sintenisii (Herter) Holub
• Huperzia somai (Hayata) Ching
• Huperzia stemmermanniae (A.C. Medeiros & W.H. Wagner) Kartesz
• Huperzia sulcinervia (Spring) Trevisan
• Huperzia taxifolia (Sw.) Trevisan
• Huperzia tenuicaulis (Underwood & Lloyd) B. Pllg.
• Huperzia verticillata auct. non (L. f.) Trevisan accepted as Huperzia acerosa (Sw.) Holub
• Huperzia wilsonii (Underwood & Lloyd) B. Pllg.
• Isoetes acadiensis Kott
• Isoetes altonharvillii L.J. Musselman & R.D. Bray
• Isoetes appalachiana D.F. Brunton & D.M. Britton
• Isoetes bolanderi Engelm.
• Isoetes boomii N. Luebke
• Isoetes braunii Durieu accepted as Isoetes tenella Léman
• Isoetes brittoni Brunton & W.C. Taylor accepted as Isoetes brittonii Brunton & W.C. Taylor
• Isoetes brittonii Brunton & W.C. Taylor
• Isoetes bruntonii D.A. Knepper & L.J. Musselman
• Isoetes bulbiforme
• Isoetes butleri Engelm.
• Isoetes canadensis (Engelm.) A.A. Eat. (unaccepted)
• Isoetes caroliniana (A.A. Eat.) N. Luebke accepted as Isoetes valida (Engelm.) Clute
• Isoetes dodgei A.A. Eat.
• Isoetes eatonii Dodge
• Isoetes echinospora Durieu accepted as Isoetes tenella Léman
• Isoetes engelmannii A. Braun
• Isoetes fairbrothersii J.D. Montgomery & W.C. Taylor
• Isoetes flaccida Shuttlw. ex A. Braun
• Isoetes flettii (A.A. Eat.) N.E. Pfeiffer accepted as Isoetes occidentalis Henderson
• Isoetes foveolata A.A. Eat. ex Dodge
• Isoetes georgiana N. Luebke
• Isoetes gravesii A.A. Eat. accepted as Isoetes eatonii Dodge
• Isoetes harveyi A.A. Eat.
• Isoetes hawaiiensis W.C. Taylor & W.H. Wagner
• Isoetes heterospora A.A. Eat.
• Isoetes hickeyi W.C. Taylor & N. Luebke
• Isoetes hieroglyphica A.A. Eat. accepted as Isoetes lacustris Linnaeus
• Isoetes howellii Engelm.
• Isoetes hyemalis D.F. Brunton
• Isoetes jeffreyi D.M. & F. Britton
• Isoetes lacustris Linnaeus
• Isoetes lithophila N.E. Pfeiffer
• Isoetes lithophylla N.E. Pfeiffer accepted as Isoetes lithophila N.E. Pfeiffer
• Isoetes louisianensis Thieret
• Isoetes macrospora Durieu accepted as Isoetes lacustris Linnaeus
• Isoetes maritima Underwood
• Isoetes melanopoda Gay & Durieu ex Durieu
• Isoetes melanospora Engelm.
• Isoetes muricata Durieu accepted as Isoetes tenella Léman
• Isoetes nuttallii A. Braun ex Engelm.