Observations by hammett2

Stems of 2 types, sterile and fertile; sterile stems branched, hollow, to 3m tall, 2cm thick, 14-30 ridged, the sheaths to 2.5 cm long, pale below, dark above; fertile stems unbranched, fleshy, to 60cm tall; rhizomes black, covered with felt, bearing pear-shaped tubers at the joints.

Delicate, palmately branched, leaves few or solitary from stout (3-5 mm thick), scaly rhizomes, but form colonies in suitable habitats. Leaves lustrous, dark-brown to purplish-black, erect stipes 15-60 cm tall, the top of the leaf stalk divided into 2 and these divisions divided again; blade 10-40 cm across, set nearly parallel to the ground; each leaflet with oblong or fan-shaped ultimate segments smooth and flat on the lower margin and cleft into ragged, rectangular lobes on the upper margin.

Large, often multi-stemmed, to 35m tall; young bark green and smooth, older bark grey-brown, ridged, and often covered with mosses, lichens, and ferns. Opposite, deciduous, 5-lobed maple leaves, 15-30 cm across, dark green above, paler below, turning yellow in the autumn; leaf stalk exudes milky juice when cut.

Plants large, upright to ascending, coarse, up to 20 cm long, with irregular, widely spaced, once-pinnate branching; stems and branches without small, green filaments (paraphyllia); uppermost portion often curved to 1 side. Leaves are 3.5-5.0 mm long, egg-shaped with long, slender tips, spreading, somewhat pleated leaves; midribes strong, double; cells elongate and irregularly thickened throughout. Infrequent sporophytes, growing from the side of the stem; stalks long; capsules inclined, curved, smooth.