1. Corallorhiza odontorhiza (Willd.) Nutt. (late coral root)

Pl. 111 c, d; Map 458

Flowering stems 5–35 cm long, the base swollen and bulblike, the raceme with 2–20 flowers. Sepals and lateral petals 3–4 mm long, greenish purple. Lip in chasmogamous flowers 2–4 mm long, white with reddish purple spots, not apparent in cleistogamous flowers. Fruits 3–7 mm long. August–November.

Scattered throughout Missouri (eastern U.S. and adjacent Canada west to Oklahoma; Mexico, Central America). Mesic upland and bottomland forests, frequently on acidic substrates; also sometimes at the edges of glades in rocky soil.

Most populations of this species in Missouri contain only individuals with cleistogamous flowers that also lack a rostellum. These plants are obligately self‑pollinated. Rare individuals with chasmogamous flowers occur uncommonly and sporadically within populations, and are apparently outcrossers, setting few fruits. Pollination in such plants is apparently by various flies, but has not been verified for the species.