Rhizomes horizontal, brownish, thick, praemorse, fleshy. Scapes 1-3, round in cross section, 0.8-2.5 dm, slender to stout, glabrous. Bracts held well above ground, sessile; blade green to bluish green, strongly to sparsely mottled, mottling becoming obscure with age, oval to suborbicular, 4-10 × 2-8 cm, base broadly attached, apex rounded-acuminate to bluntly parallel sided-acuminate (rounded basally to its broad attachment). Flower erect, odor pungent, spicy; sepals displayed above bracts, spreading, green, variously streaked with maroon, lanceolate-oblanceolate, 9-35 × 4-8 mm, margins entire, apex rounded-acuminate; petals long-lasting, erect, ± connivent, ± concealing stamens and ovary, maroon, brownish maroon, green, or yellowish green, not spirally twisted, oblanceolate to elliptic, occasionally almost orbicular, 1.7-3.5 × 0.7-2 cm, thick-textured, narrowed near basal attachment (but not truly clawed), margins entire, apex gradually rounded-tapered to acute; stamens straight, 10-23 mm; filaments red-purple, 2-5 mm, dilated basally; anthers erect, straight, gray-purple, 9-16 mm, thick, dehiscence introrse; connectives purplish brown, straight, projecting 2-5+ mm beyond anther sacs; ovary greenish white basally, purple distally, ovoid to globose, 6-angled, pyramidally narrowed to stigmas, 4-8.5 mm; stigmas erect, divergent-recurved, distinct, purple, subulate, 1-5 mm, ± fleshy. Fruits baccate, dark greenish purple, odorless, subglobose, 6-angled, angles somewhat winglike, pulpy, not juicy. 2n = 10. Flowering spring (Mar--early May). Rich woodlands, limestone districts, calcareous soils, floodplains, riverbanks, clayey alluvium, less fertile soils, high, dry limestone woods, persists under light pasturing, in fencerows and brushy areas after lumbering; 100--300 m; Ala., Ark., Ill., Ind., Kans., Ky., Md., Mich., Mo., N.Y., N.C., Ohio, Okla., Pa., Tenn., Va., W.Va. Trillium sessile is rather uniform throughout its range, with few color forms.