This native perennial fern develops an erect and rather stout stem about 2½' tall, from which there extends a single compound leaf about 3½' long and 3' across. In shady areas, the compound leaf usually extends horizontally in relation to the ground, while in sunny areas it is more ascending. The compound leaf varies in color from yellowish green to medium green. The compound leaf has an irregular structure; it is mostly bipinnate-pinnatifid and, to a lesser extent, ternately pinnate (3-pinnate). Each compound leaf is divided into 3 major branches (1 central, 2 lateral). A single branch of the compound leaf has a pinnate-pinnatifid or bipinnate structure; it is triangular in outline. The rachis of each branch is light green and hairless (or nearly so). There are about 12 pairs of leaflets along the central axis (rachis) of each branch; the leaflets toward the base of the branch are much longer than the leaflets toward its tip. The leaflets toward the base are more likely to be odd-pinnate, while the leaflets toward the tip are more likely to be odd-pinnatifid. Individual leaflets have 1-15 pairs of subleaflets or lobes; they are usually oblong in shape. The terminal lobes (or subleaflets) are elongated in shape and finger-like in appearance; they are 3-6 mm. (1/81/4") across and 2-4 times longer than wide. The margins of the subleaflets and lobes are smooth and sometimes slightly undulate; they bend downward. The reproductive structures (indusia, sporangia) are located along these rolled margins on the underside of the compound leaf. These reproductive structures are produced sparingly; when they occur, the spores are usually released during summer or fall. The root system system is fibrous and rhizomatous; individuals rhizomes can extend many yards (or meters), sending up new vegetative shoots every 1-5 feet. As a result, sizable colonies of plants are fairly common. The growing tips of rhizomes are either glabrous or sparsely white hairy. The compound leaves are deciduous and sensitive to frost; they die down and turn brown during the winter.