2. Botrychium dissectum Spreng. (cut-leaf grape fern) Pl. 9c,d,e; Map 45

Leaves 15–45 cm long. Vegetative portion leathery, 2–4 times pinnately compound. Uppermost pinnae lanceolate to linear, the base mostly truncate to rounded, the tip usually acute, the margins minutely toothed to lacerate. Pinnules sometimes lobed. Fertile portion 2–3 times pinnately compound, 1.5–2.5 times as long as the vegetative portion, arising from the lower 1/3 of the common petiole, the vegetative leaf blade long-stalked. 2n=90. August–November.

Scattered nearly throughout Missouri (eastern U.S. west to Texas, Canada, West Indies). Bottomland forests to mesic forests of ravines, less commonly in drier forests; also sometimes along edges of pine plantations and under trees and in thickets of old fields that are reverting back to forests.

Botrychium dissectum is a member of subgenus Sceptridium (Lyon) R.T. Clausen. For a discussion of the difficulties in separating this species from the closely related B. biternatum, see the treatment of that species. There are two intergrading patterns of dissection of the sterile leaf blades in B. dissectum. Plants with the pinnules minutely toothed and sparsely lobed have been called f. obliquum (Muhl.) Fernald (var. obliquum (Muhl.) Clute) (Pl. 9c,d), whereas those with the pinnules dissected and lacerate are f. dissectum. The two forms usually grow together, although f. obliquum is the more common of the two. Tryon (1936) suggested that individual plants may produce the two types of leaves during different years. In both forms, the leaves are produced in early summer and turn a reddish bronze color prior to overwintering. Previous season's leaves usually wither at the time the new leaves develop.