St. Lawrence grapefern, botryche à limbe rugueux

Botrychium multifidum (S.G. Gmelin) Ruprecht forma dentatum R.M. Tryon

Trophophore stalk 2 to 15 cm, 1--2.5 times length of trophophore rachis; blade green, finely rugulose and convex distally, 2--4-pinnate, to 15 × 26 cm, somewhat herbaceous. Pinnae to 9 pairs, usually approximate, horizontal to ascending, distance between 1st and 2d pinnae not or slightly more than between 2d and 3d pairs, divided to tip. Pinnules obliquely and angularly trowel-shaped to spatulate, margins usually denticulate, apex acute, venation pinnate. Sporophores 2-pinnate, 1--2 times length of trophophore. 2 n =90.

Leaves green over winter, appearing in midspring. In open fields and secondary forests over wide range in vicinity of St. Lawrence Seaway; 200--1000 m; Ont., Que.; Mich., Minn., N.Y., Vt., Wis.

The name "rugulosum" refers to the tendency of the segments to become more or less wrinkled and convex. Botrychium rugulosum occurs with B . dissectum , B . multifidum , and rarely B . oneidense . It is often found in small stands of only 5--10 individuals, but some populations number over 100.