Trillium erectum is a perennial herb, monocotyledon 20-40 cm tall from a stout rhizome to 3 cm thick, stems 1-several, 15-40 cm tall.
Leaves three, in a whorl at top of stem, just below flower stalk, leaf stalk almost none, no stalk, blade 4-19 cm long and wide, broadly egg-shapd to rhombic, tip long-pointed, base narrowed to a point, major veins palmate at base, secondary veins netted.
Flowers dark purple to brownish-purple, petals 3, 1.5-6 cm long, 1-3 cm wide, narrowly egg-shaped, tip pointed, stamens longer than stigmas, ovary purple, sepals 3, narrow, alternating with petals, flower foul-smelling; blooms April-early June.
Fruit dark red, 6-ribbed, 3-parted, developing on top of flower parts, seeds several.
Wetland status: FACU.
Frequency in NYC: Very infrequent.
Habitat: Rich, moist, undisturbed woods, slightly acid soil. Most trilliums are quite shade tolerant.