A tiny woodland orchid that rewards a close look. Autumn Coralroot sends up slender, leafless stems late in the growing season, carrying small brownish-purple flowers with pale lips. Its swelling ovaries can be more noticeable than the flowers themselves.
Autumn Coralroot field photograph by Brian Woolman. Tap the photo to enlarge.
Family: Orchidaceae
Genus: Corallorhiza
Growth: Perennial orchid with leafless flowering stems
Bloom: August–October in the Upper Midwest
Height: Often 5–8 inches in the Upper Midwest; height varies
Habitat: Shaded upland woods and leaf litter
Other common names: Fall Coralroot · Late Coralroot · Small-flowered Coralroot
Bloom timing and height vary with location and growing conditions. Regional field notes: Minnesota Wildflowers.
Explore photographed sightings and their locations.
Autumn Coralroot’s hanging capsules eventually split open, releasing seeds so small they resemble dust. Wind can carry these tiny seeds away from the parent plant. Reaching the ground is only the beginning: in nature, orchid seeds need suitable fungi to help them germinate and begin growing.
From August through October in the Upper Midwest, look among fallen leaves in shaded deciduous or mixed upland woods. Scan close to the ground for slender brownish stems and tiny pale flower lips. These small orchids blend into leaf litter and are easily overlooked.
Autumn Coralroot obtains its nourishment through fungi associated with its underground rhizome. This way of life is called mycoheterotrophy. It does not feed directly on dead leaves, even though leaf litter is part of its woodland home. The flowering stem is only the visible part of the plant.
Some Autumn Coralroot flowers open, while others remain closed and self-pollinate. Closed flowers are called cleistogamous. A flower that looks like a tiny unopened bud may already be functioning. These photographs show pale lips projecting from several flowers; they do not establish a botanical variety.
Spotted Coralroot generally has larger flowers and a lip with small side lobes; Autumn Coralroot has an undivided lip. Spring Coralroot can also have an undivided lip, so flowering season and flower details matter together. Autumn Coralroot blooms late in the year. Capsules alone are less reliable for separating species.
Native across much of eastern and central North America, including Illinois and Wisconsin. It occurs locally in suitable woodland habitat and can be easy to overlook.
Reported U.S. distribution
AL, AR, CT, DC, DE, FL, GA, IA, IL, IN, KS, KY, LA, MA, MD, ME, MI, MN, MO, MS, NC, NE, NH, NJ, NY, OH, OK, PA, RI, SC, SD, TN, TX, VA, VT, WI, WV
State records do not mean the orchid occurs in every county or woodland. Distribution source: North American Orchid Conservation Center.
Observations show reported sightings; they do not define the plant’s complete native range.
Study Autumn Coralroot’s tiny flowers and leafless stem, then practice recognizing it in the wildflower quiz.
North American Orchid Conservation Center — biology, range, and flower forms
Flora of North America — diagnostic flower characters
University of Wisconsin — Autumn Coralroot
Minnesota Wildflowers — regional flowering season
North American Orchid Conservation Center — dust seeds and germination
Illinois Wildflowers — capsules and seed dispersal
