''Isoetes'' × ''eatonii'', or Eaton's quillwort, is a hybrid between '' I. engelmannii'' and '' I. tenella''. It can be found in ponds and slow moving rivers in Canada or in several

New England New England is a region consisting of six states in the Northeastern United States: Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, and Vermont. It is bordered by the state of New York (state), New York to the west and by the ...

states. In Canada, it has only been found in the Severn River in

Ontario Ontario is the southernmost Provinces and territories of Canada, province of Canada. Located in Central Canada, Ontario is the Population of Canada by province and territory, country's most populous province. As of the 2021 Canadian census, it ...

.Kott, L.S.; Bobbette, R.W.S. 1980 ''Isoetes eatonii, a quillwort new for Canada''. Can. Field-Nat. 94:163-166 In the United States, it has been found in Pennsylvania, New Jersey, and New York. It bears 12-100 long yellowish green leaves, each fine, soft, and 8 to 45 centimeters long. The unspotted tan colored sporangium are 12 millimeters long and 5 millimeters wide. The velum covers a sixth to a quarter of the sporangium. The elongated ligule is 3.5 millimeters long. The flattened white megaspores are 320 to 530 micrometers in diameter and bear short spiny ridges. The round microspores are 22 to 25 micrometers long.

References

eatonii Flora of Eastern Canada Flora of the Eastern United States Plant nothospecies {{Lycophyte-stub