Contemporary Circumscription Compared with A Utah Flora 4th ed.

Bio430

Isoetaceae

No difference at the family level.

Key Features

Isoetes are aquatic (at least seasonally), grass like, with round, elongate microphylls possessing expanded leaf bases with sporangia on their inner surface.  The leaves are ligulate and plants are heterosporous.  Isoetes are evolutionarily interesting because they can perform CAM photosynthesis (like cacti).