Ophioglossum pusillum is an easy species to identify in Wisconsin, but it is uncommon and may be easily overlooked. The blade is simple and there is a separate fertile branch (sporophore) arising near the base of the blade. Blades are up to 10 cm long and broadest near the middle. Our only other fern with a simple blade is Asplenium rhizophyllum which does not have a separate fertile branch and the blades are widest near the base.

O. pusillum is known from Nebraska to Ontario, east to New Jersey and New Brunswick. It is also known from British Columbia and the northwestern U.S. In Wisconsin it is a "special concern" species, documented from fewer that 40 scattered localities, and is apparently absent over a large portion of northern Wisconsin. Habitats are mostly moist, grassy sites.