Publication: Trans. Acad. Sci. St. Louis. 4: 385. 1882.
selected vouchers: WTU
Notes: FNA2: "In many respects, Isoetes howellii appears similar to I. melanopoda. Small plants with leaves less than 10 cm and megaspores less than 420 μm diam. have been called I. howellii var. minima (A. A. Eaton) N. E. Pfeiffer."