Isoetes × eatonii

Isoetes × eatonii, or Eaton's quillwort, is a hybrid between I. engelmannii and I. tenella.[1] It can be found in ponds and slow moving rivers in Canada or in several New England states. In Canada, it has only been found in the Severn River in Ontario.[2] In the United States, it has been found in Pennsylvania, New Jersey, and New York.[3] 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.[3]

Isoetes × eatonii
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Clade:	Lycophytes
Class:	Lycopodiopsida
Order:	Isoetales
Family:	Isoetaceae
Genus:	Isoetes
Species:	I. × eatonii
Binomial name
Isoetes × eatonii Dodge
Synonyms
Isoetes gravesii A.A. Eat.

References

1. "Isoetes × eatonii R. Dodge (pro sp.) [engelmannii × tenella] quillwort". United States Department of Agriculture. Retrieved 2015-05-23.
2. Kott, L.S.; Bobbette, R.W.S. 1980 Isoetes eatonii, a quillwort new for Canada. Can. Field-Nat. 94:163-166
3. Cody, William; Britton, Donald (1989). Ferns and Fern Allies of Canada. Agriculture Canada.