Isotria medeoloides, commonly known as small whorled pogonia or little five leaves, is a terrestrial orchid found in temperate Eastern North America.
The orchid's range is from southern Maine south to Georgia and west to southern Ontario, Michigan, and Tennessee. A population was found in Missouri in 1897,[1] but the plant is no longer believed extant there.[2]
It has always been considered a rare species, often legendarily so. It has been called "the rarest orchid east of the Mississippi",[3] and findings of it are covered by the media, such as the one found in Vermont in 2022.[4]
The plant's habitat includes hardwood and conifer-hardwood forests, where it is found in leaf litter along small "braided" intermittent streams. Its native range includes the Appalachian Mountains and Great Lakes region.
Isotria medeoloides is a rhizomatous herb producing a waxy gray-green stem up to about 25 centimeters tall. The gray-green leaves are up to 8.5 centimeters long by 4 wide and are borne in a characteristic whorl.
The flower has green and green-streaked yellowish petals measuring between 1 and 2 centimeters long.[5]
The plant is listed as a threatened species by the U.S. Fish and Wildlife Service, having been downlisted from endangered status in 1994 as more populations were discovered, and several were given protection.[2] It is listed as an endangered species by most states or provinces within its range.[6] There are about 104 populations known to exist, but most of these are small, containing fewer than 25 plants.[3]
The main threat to the species' existence is the destruction of its habitat.[3] Other threats include wild pigs, off-road vehicles, predation by deer and slugs, vandalism, and collection.[7]
This orchid is sometimes confused with the common Indian cucumber (Medeola virginiana), which has similar whorled leaves and grows in similar habitat types. The species name medeoloides is a reference to this similarity.[3]
Anecdotal tales of the species only appearing at decades-long intervals do not appear to be supported by field studies. The plant can usually remain dormant for up to three years.[3]