This herbaceous plant is a monocarpic perennial. It persists as a rosette of 3-30 basal leaves for 5-15 years (or more), finally bolting as a flowering plant that becomes 3-8' tall for a single season, and then dying. The basal leaves are up to 14" long and 4" across; they are oblong-elliptic to broadly oblong-elliptic in shape and smooth along their margins. The upper surfaces of the basal leaves are medium green and glabrous with prominent central veins; they are deciduous. The central stem of a flowering plant is light green to purple, glabrous, terete (circular in cross-section), rather stout, and unbranched. Along its entire length, there are whorls of 4-5 leaves (rarely more) that become gradually smaller in size as they ascend the central stem. Individual whorled leaves are 3-12" long and ¾-3" across; they are oblong-elliptic, oblong-lanceolate, or oblong-oblanceolate in shape with smooth margins. The upper surfaces of these leaves are dark green and glabrous with prominent central veins; they are also deciduous. The central stem terminates in a panicle of flowers up to 2' long (typically 50-100 flowers per panicle). This panicle is narrowly pyramidal in shape with spreading to ascending lateral branches. The terminal branches produce clusters of 2-6 flowers each on pedicels ¾-2" long. Each flower is ¾-1¼" across, consisting of a shallow corolla with 4-5 spreading petaloid lobes, a shallow calyx with 4-5 spreading lobes, 4-5 stamens, and a superior ovary with a single style. Usually, the flowers are divided into 4 parts, rather than 5. The corolla lobes are oblong-lanceolate or oblong-elliptic in shape; they are mostly greenish white with purple specks or streaks, although their bases may be tinted pale yellow or pale pink. Toward the middle of each corolla lobe, there is a conspicuous nectar pad that is heavily fringed. The bases of these nectar pads are surrounded by rings of green. The calyx and its lobes are medium green and glabrous; individual lobes are linear-lanceolate and up to ½" long. The superior ovary is light green. The peduncle, lateral branches, and pedicels of the inflorescence are light green to purple, glabrous, and terete. At locations where there are divergent branches within the inflorescence, there are pairs of leafy bracts about 1-3" long that are linear-lanceolate or linear-oblong in shape. The blooming period occurs from late spring to early summer, lasting about 3 weeks. The flowers within a panicle bloom at about the same time. Individual plants in a colony have a tendency to bloom synchronically (during the same year at the same time), which facilitates cross-pollination of the flowers. Afterwards, the flowers are replaced by ovoid seed capsules about ½-¾" in length; these capsules are strongly beaked from the persistent styles. At maturity, these capsules become dark brown and split open to release their seeds. Each capsule contains 4-14 dark brown seeds that are crescent-shaped and winged. The root system consists of a fleshy taproot.