Leaves and stems:

The leafy frond, called a trophophore, is single, 2 or 3 times compound, more or less triangular in outline, 4 to 15 cm (to 6 inches) long, 5 to 20 cm (to 8 inches) wide, on a stalk 1 to 4 inches long. The branches (pinnae) each have a few to several segments (pinnules), the largest typically at the base of the branch, the terminal pinnule typically lobed within 1 cm (3/8 inch) of the tip. At maturity, the largest pinnules are 9 to 17 mm (~1/3 to 2/3 inch) long, 4 to 8 mm (~1/6 to 1/3 inch) wide. The surface is generally flat, the veins not prominent. Pinnule tips are rounded to bluntly pointed, the edge smooth, scalloped or obscurely and irregularly toothed.

Spores:

The fertile frond, called a sporophore, is up to 30 cm (12 inches) long, 1.5 to 2.5 times as long as the tropophore, with numerous branches, each with several to many round capsules of spores (sporangia). Spores are released starting in late September.

Notes:

Leathery Grapefern is the most common of the 4 Sceptridium species (formerly lumped in Botrychium) known to be in Minnesota. It has a circumboreal distribution, native to Europe, Asia and North America and, in Minnesota, is found in a variety of habitats, including woodlands, prairies, wetland edges, and around old mine dumps and tailings basins, most often in moist soil, less often dry. Sceptridium is characterized by a single compound, generally triangular, evergreen leaf (tropophore) that emerges in spring, persists through winter, and withers away the following summer. The fertile sporophore is not always produced, but when present rises well above the tropophore.

Sceptridium multifidum is distingushed by segments (pinnules) mostly rounded at the tip, the edge smooth, scalloped or obscurely or irregularly toothed, veins not prominent so the surface is fairly flat. The largest pinnules are at the base of a branch and are 9 to 17 mm long, 4 to 8 mm wide; the terminal pinnules are typically lobed near the tip. A mature tropophore is 4 to 15 cm (to 6 inches) long, 5 to 20 cm (to 8 inches) wide, and is the largest of the Minnesota species, though the size is quite variable even within a population.

Most similar is Sceptridium rugulosum, with which it may grow. Both have a few to several pairs of pinnules on each branch, typically the largest at the base and the terminal pinnule lobed within 1 cm of the tip. In most cases S. rugulosum is overall a smaller plant, the largest pinnules 4 to 9 mm long and 2 to 5 mm wide, the tip edges more distinctly and regularly toothed, the shape more angular, and the veins more prominent so the surface has a more wrinkled or ridged texture. When in doubt, the experts say the size of the largest pinnules should be the more important factor.

The difference with the other two species, S. dissectum and S. oneidense, is they have fewer pinnules per branch, the terminal pinnule largest and more elongated, unlobed or lobed more than 1 cm from the tip, the smallest pinnules usually at the base of the branch, and all are distinctly toothed around the edges.