Leaves and stems:

The leafy frond, called a trophophore, is single near the top of the stem, oblong in outline, with 3 to 7 pairs of leaflets (pinnae), often closely spaced and even overlapping and not typically folding in towards the stalk. The trophophore is 2.5 to 7 cm (1 to 2¾ inches) long, held erect, the stalk 0 to 8 mm (to 1/3 inch) long. The stem below the tropophore is 3 to 7 cm long.

The lowest pinnae pair are perpendicular to the stalk or nearly so, the next higher pairs becoming more ascending. Pinnae are mostly fan-shaped, the sides straight or concave, the curvature usually strongest at the base, and span an angle of 90 to 180 degrees with the lowest pair widest, usually at least 120 degrees. The tip edge is smooth or scalloped, sometimes irregularly notched.

Fruit:

At the top of the stem is the fertile frond, called a sporophore, 9 to 15 cm (to 6 inches) long, rising above the tropophore at the end of a stalk usually longer than the tropophore at maturity. The sporophore typically has numerous short branches, each with a few to several round capsules of spores (sporangia) that mature starting in June, turn yellow at maturity, then brown after spores are released by mid July.

Notes:

New World Moonwort was recently split from the circumboreal species Botrychium lunaria, which has a North American range now limited to northern Canada, Alaska and Greenland, where B. neolunaria ranges south of that. According to the DNR, it has a sporadic distribution in Minnesota, with most populations found in Cook, Lake of the Woods, and Roseau counties. Habitats are primarily deciduous and mixed forests, but also grassy roadside openings, talus slopes, cliffs, and old fields and homesteads, often in deep thatch. It is usually found as scattered individuals and mixed with other Botrychium species. It was listed as a Threatened species in 1996.

Its form varies depending on habitat. In dense shade, the pinnae tend to be smaller, fewer and widely spaced, where in sunnier spots the pinnae tend to be more crowded and often overlapping. In either case, the tropophore is stalkless or short stalked, pinnae are fan-shaped, the lowest pinnae pair tends to be perpendicular to the stalk or nearly so and usually spans an angle of 120 to 180 degrees. The pinnae above it tend to be more ascending and span 90 degrees or more. Pinnae tips are smooth, scalloped or irregularly notched.

Similar is B. minganense (Mingan Moonwort), with which it may grow; it typically has more pinnae that are all ascending, narrower (spanning 60 to 120 degrees), often widely spaced, and the tropophore is more distinctly stalked; this can be very difficult to distinguish from deep shade forms of B. neolunaria. Also similar is B. crenulatum (Crenulate [or Scalloped] Moonwort), very rare in Minnesota, which is typically a more delicate plant, has fewer pinnae pairs (2 to 5), the tropophore stalk is up to 17 mm (2/3 inch) long, and robust specimens often have pinnae deeply and irregularly notched and do not usually overlap.

The shape of the pinnae may be similar to other Botrychiums as well, but these can all be variable on individuals so it's helpful to examine multiple plants within a population (if you can find them). Having said that, Botrychium identification is difficult even for the experts so don't be discouraged if you struggle to get it down to species.