Leaves and stems:

The leafy frond, called a trophophore, is single near the top of the stem, oblong in outline, with 3 to 6 pairs of leaflets (pinnae), the lowest pair typically largest and well separated from the next lowest pair, the remaining pairs with shorter gaps between them. The trophophore is 1.4 to 3.5 cm (to ~1½ inches) long, held more or less erect, the stalk 4 to 8 mm (to 1/3 inch) long. The stem below the tropophore is 3 to 7 cm (to 2¾ inches) long.

Pinnae are ascending, broadly to narrowly spoon or spatula-shaped, straight or concave on the sides, spanning an angle of 25 to 45 degrees, and tend to fold in towards the stalk. The tip edge is smooth or irregularly notched or asymmetrically lobed; when lobed, the upper lobe is usually largest and the total width may exceed 45 degrees.

Spores:

At the top of the stem is the fertile frond, called a sporophore, 3 to 8 cm (to ~3 inches) long, usually noticeably larger than the trophophore and rising above it at the end of a stalk half or more as long as the trophophore. The sporophore typically has numerous short branches, each with a few to several round capsules of spores (sporangia) that mature starting in June then turn brown when spores are released in July.

Notes:

Frenchman's Bluff Moonwort is one of the rarest ferns in North America. According to the DNR, it was actually unknown to science when it was first discovered on Frenchman's Bluff in Norman County in 1986, and as of this writing the only other known populations in North America are in Kittson County, in the Black Hills of South Dakota, and in Glacier National Park in Montana. The DNR designated it Endangered in 1996.

While most Moonworts are known as forest species, B. gallicomontanum is one of the few prairie specialists, found in open tall grass or short grass prairie and savanna, in dry sandy or gravelly soil. It emerges in spring, matures June-July, then withers away. The tropophore is its most distinguishing characteristic: distinctly stalked, the 3 to 6 pair of pinnae strongly ascending and folded in, the gap between the lowest 2 pairs typically noticeably larger than between the remaining pairs. Pinnae are narrowly spoon-shaped, tips mostly rounded, the top edge smooth or irregularly notched, and span 45 degrees or less, though lobed pinnae may be wider. The sporophore is typically rather larger than the tropophore and rises well above it, on a stalk at least half as long as the tropophore.

Most similar is the more common B. campestre (Prairie Moonwort), with which it may grow; its tropophore is stalkless or nearly so, pinnae are more evenly spaced, the sporophore is proportionately smaller than that of B. gallicomontanum, and its stalk less than half as long as the tropophore, usually ¼ or less. B. pallidum (Pale Moonwort) is somewhat similar, but it is typically a pale gray-green or blue-green color, its pinnae are wider, more fan-shaped and not as strongly ascending, and it often grows in clumps.

The shape of the pinnae, and sometimes the spacing, 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.