Rhizomes short, thick, praemorse. Scapes 1-2, often with numerous offsets forming heavy clumps, round in cross section, 1.5-6 dm, ± robust, glabrous. Bracts sessile; blade bright green, lacking dark pigmentation, major veins prominent, broadly rhombic to ovate-rhombic, 5-20 × 5-20 cm, about as broad as long, widest near middle, base attenuate, apex acuminate. Flower erect, ascending, or proximal to but above bracts, odor fetid, like a wet dog; perianth open, flat; sepals flat to sulcate apically, green, often streaked or overlain with maroon, occasionally entirely dark maroon, lanceolate-acuminate, 10-50 mm, equaling petals, ± 1/2 petal width, texture leafy, margins entire, apex acuminate; petals spreading, carried in same plane as sepals or ascending slightly, dark reddish brown, maroon, purple, or white, sometimes pale yellow, major adaxial veins prominent and appearing somewhat engraved, usually flat, lanceolate, ovate-lanceolate, or occasionally ovate, 1.5-5 × 1-3 cm, 2 times sepal width, widest near base, heavy-textured, apex acuminate; stamens erect to slightly recurved, 5-15 mm; filaments white, pinkish, or dark purple, ± equaling anthers, but variable within local populations, thin; anthers erect or weakly recurving, dark maroon, grayish maroon, or yellowish, strongly yellow when pollen exposed, 5-12 mm, dehiscence introrse; ovary dark purple to maroon, even in white-flowered forms, ovoid, elliptic to globose, 6-angled, angles forming very low ridges when fruit is ripe, 5-10 mm, broadly attached at base; stigmas recurved, distinct, dark purple, not lobed adaxially, subulate, short, 3-7 mm, ca. 1/2 or less length of ovary at anthesis, fleshy; pedicel straight, erect, or somewhat declined but not strongly recurved below bracts, 1-10+ cm. Fruits dark maroon, weakly fragrant of fruit, ± globose to slightly pyramidal, 1-1.6 × 1-1.5 cm, juicy. 2n = 10.
Stem 2-4 dm; lvs usually broadly rhombic, about as wide as long, narrowed with nearly straight margins from near the middle to the acute base; peduncle erect to lateral, mostly 3-8 cm, up to ca twice as long as the sep, the ±foetid fls held ±above the lvs; sep lanceolate to lance-ovate or seldom ovate, flat or weakly sulcate-tipped, ca equaling or somewhat shorter than the pet; pet normally maroon (white, yellow, or green), lanceolate to lance-ovate or seldom ovate, 2.5-6 cm, acute, widely spreading from the base, exposing the dark ovary; stamens shorter to somewhat longer than the ovary, the filaments mostly a fourth to half as long as the anthers; fr dark red, ovoid-globose, with 6 wing-ribs; 2n=10. Moist woods; Que. and Ont. to Md. and O. and reputedly ne. Ill., s. to the mts. of N.C., Ga., and Tenn. Apr., May.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.