Neil T. Luebke, Jessica M. Budke
American Fern Journal 93 (4), 184-190, (1 October 2003) https://doi.org/10.1640/0002-8444(2003)093[0184:ITIAOQ]2.0.CO;2
Isoëtes tennesseensis, an octoploid species with a chromosome count of 2n = 88, is described. It occurs in the Hiwassee River in Tennessee. Past collections of this species have been misidentified as Isoëtes macrospora (= I. lacustris). Isoëtes tennesseensis differs from I. lacustris in chromosome number, megaspore and microspore morphology and distribution. Speculation on the origin of this new species is presented.