• Isoetes Linnaeus, 1753
• 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.
• Isoetes occidentalis Henderson
• Isoetes orcuttii A.A. Eat.
• Isoetes paupercula (Engelm.) A.A. Eat. accepted as Isoetes occidentalis Henderson
• Isoetes piedmontana (N.E. Pfeiffer) C.F. Reed
• Isoetes piperi A.A. Eat. accepted as Isoetes occidentalis Henderson
• Isoetes prototypus D.M. Britt.
• Isoetes pseudotruncata D.M. Britton & D.F. Brunton accepted as Isoetes maritima Underwood
• Isoetes pygmaea Engelm. accepted as Isoetes bolanderi Engelm.
• Isoetes riparia Engelm. ex A. Braun
• Isoetes saccharata Engelm.
• Isoetes setacea Lam.p.p. accepted as Isoetes tenella Léman
• Isoetes tegetiformans Rury
• Isoetes tenella Léman
• Isoetes truncata (A.A. Eat.) Clute
• Isoetes tuckermanii A. Braun
• Isoetes valida (Engelm.) Clute
• Isoetes virginica N.E. Pfeiffer