Amerorchis rotundifolia is a rare and attractive orchid with a single basal leaf and purple- or pink-spotted white flowers. The plant as a whole is small, reaching 10-20 cm, found in woodlands, meadows, and along streambanks. The plant grows from a short, rhizome, with fleshy roots typical of orchids. The single leaf is rounded to elliptic, simple and entire-margined, 3-7 cm long. The flowering stem is narrow, leafless, bearing 2-4 flowers. Like all orchids, the flowers are bilaterally symmetric. The sepals and lateral petals are white to violet-pink. The prominent lip is lobed and white with purple spots, 5-10 mm long and, the spur 3-7 mm long. The fruit is and ellipsoid capsule containing many tiny seeds. Amerorchis rotundifolia could be confused with other orchids. However, in other orchids with spotted flowers (such as Calypso bulbosa and Cypripedium guttatum), the flower is much larger and solitary. The genus Platanthera has members in Alaska with several small flowers and a single leaf, but those flowers are never violet-spotted.
Amerorchis rotundifolia is perennial and typically flowers mid-summer.
This species is monoecious, with bisexual flowers. Amerorchis rotundifolia has large, showy flowers but lacks any nectar or fragrance. Insects that enter the flower have sticky packets of pollen ('pollinia') stuck to their heads. Visiting another orchid will release the pollinia and fertilize the flower. Observations of a population of this species in Canada found that flowers were visited by bees and dipteran flies (Catling and Kostiuk 2011). The authors also observed fruit set of 25-44% of flowers, extremely high for orchids, which are often pollen-limited. They produce extremely tiny seeds, which are wind dispersed. A. rotundifolia is dependent on its mycorrhizae, like many orchids.
Amerorchis rotundifolia is a North American species that occurs across the boreal region of the continent and reaches the coast of Greenland. In Alaska, the species is usually locally rare and occurs in scattered localities in southern valleys of the Brooks Range, northeast to the Black and Porcupine Rivers, and south to the Cook Inlet area. Amerorchis is known from a single locality Denali in the vicinity of the Park Road near Igloo Creek.