White Irisette (Sisyrinchium dichotomum)
Family: Iris (Iridaceae)
Federal Status: Endangered, listed September 26, 1991
Best Search Time: Late-May through July
Description: White irisette is a perennial herb that lives in areas with partial sun. It generally grows from 10 - 16 inches (25.4 – 40.6 centimeters) tall and has winged stems. An individual White irisette plant is typically defined as a cluster of stems arising from fibrous roots. There may be 10 or more stems on one plant. White irisette flowers from late May through July. The seeds are very small and black and three to six seeds are contained in each capsule.
Habitat: The species is found on mid elevation slopes, characterized by open, dry to moderate-moisture oak hickory forests. White irisette usually grows in shallow soils on regularly disturbed sites (such as woodland edges and roadsides) and over rocky, steep terrain.
Distribution: White irisette is known from Henderson, Polk and Rutherford Counties, North Carolina; and Greenville County, South Carolina.
Threats: White irisette is threatened by many human caused disturbances, such as residential development, road construction, and possibly herbicide use. It is also indirectly affected by the extirpation of elk and bison and possibly the suppression of fire. The elimination or suppression of these natural disturbances allows vegetative succession to occur, often accompanied by exotic invasive plants that out compete this native species.
References:Buchanan, M.F. and J.T. Finnegan. 2010. Natural Heritage Program List of the Rare Plant Species of North Carolina. N.C. Natural Heritage Program, Raleigh, NC.
U.S. Fish and Wildlife Service. 1995. White Irisette Recovery Plan. U.S. Fish and Wildlife Service, Atlanta, Georgia. 22 pp.
For More Information on White Irisette...
- U.S. Fish and Wildlife Service Environmental Conservation Online System
- White Irisette Recovery Plan
- U.S. Department of Agriculture Natural Resource Conservation Service Plants Database
- Center for Plant Conservation species profile
Mara Alexander, Fish and Wildlife Biologist, 828-258-3939 ext. 238
Species profile revised on September 15, 2011.