About Aphyllon uniflorum (L.) A.Gray
Aphyllon uniflorum (formerly classified as Orobanche uniflora) grows between 3 and 10 centimeters tall, with just one purple-to-white five-petaled flower per stem. Its corolla is two-lipped, finely fringed, and has five similar lobes. The main stem grows underground, with only the flower-bearing pedicels visible above ground, and each pedicel holds exactly one flower. Stems are grayish tan, and the plant has no leaves on any part of its body or its offshoots. It reproduces via seeds, which develop in a two-chambered fruit that produces many seeds. This plant is parasitic, feeding on the root systems of other plants, most commonly species in the stonecrop genus Sedum. It does not produce chlorophyll, and instead obtains nutrients including carbohydrates from host plants; since it has no chlorophyll, it has no green-colored parts. Botanists have not reached a consensus on whether this species' flowers are pollinated by insects or self-pollinate. The life expectancy of Aphyllon uniflorum is unknown. This species closely resembles Aphyllon fasciculatum (formerly Orobanche fasciculata), but the two can be distinguished by their bracts and number of flowers. A bract, which is a small leaf-like structure, forms at the junction where each flower stalk attaches to the underground stem. A. uniflorum has hairless bracts, while A. fasciculatum has hairy bracts. A. uniflorum produces one to three flowers per stem branch, whereas A. fasciculatum produces three to ten flowers per stem branch. A. fasciculatum also has pinkish to creamy-white flowers, while A. uniflorum has violet-tinged flowers. This species grows in woods, thickets, mountains, and along stream banks, and it is widespread across much of North America. Unlike other species formerly placed in the genus Orobanche, A. uniflorum is most commonly found in forests. It can survive in both full sun and shaded environments, and grows in a wide variety of soil types. Its habitat is limited to locations with abundant host plants, and it is unlikely to survive in areas where its host plants are sparse. One specimen of the species is held in the botany department of the Smithsonian National Museum of Natural History, and another specimen has been photographed at Hells Canyon National Recreation Area. It is classified as rare or vulnerable in 17 U.S. states and five Canadian provinces. In Minnesota, it was listed as a species of Special Concern in 1984, and reclassified as endangered in 2013; when it was first listed as Special Concern in Minnesota, only seven known populations existed.
