Veratrum virginicum
From Illinois Wildflowers
This is a herbaceous perennial plant about 2½–5' tall. At its base, there is a rosette of arching basal leaves 10-20" long and ½–1¼" across; they are medium green to yellowish green, glabrous, linear in shape, entire (toothless) along their margins, and often folded upward along their midveins. Leaf venation is parallel. A few alternate leaves occur along the central stem of this plant; they are similar to the basal leaves, except smaller in size. The central stem terminates in a panicle of flowers about ¾–2' long and about one-half as much across. Each flower has a white corolla with 6 spreading tepals, 6 stamens with white filaments, 3 white styles, and a light greenish yellow ovary.When it is in full bloom, Virginia Bunchflower is very showy and attractive