Harperella (Ptilimnium nodosum)
Family: Carrot (Apiaceae)
Federal Status: Endangered, listed September 28, 1988
Best Search Time: July through October, only in periods of low water
Taxonomic Note: Recent electrophoretic and morphologic data suggest the existence of three distinct species from what was all formerly considered Ptilimnium nodosum sensu stricto: Ptilimnium fluviatile (Gulf River Harperella) occurs on rocky riverbeds in the mountains of Alabama and Arkansas. Ptilimnium nodosum (Pond Harperella) occurs in upland depression ponds and in seepage on granite outcrops in the coastal plain of Georgia and South Carolina. Ptilimnium viviparum (Atlantic River Harperella) occurs in rocky riverbeds in the Piedmont and Mountains of North Carolina, Virginia, Maryland and West Virginia.
Description: Harperella in North Carolina (described as Ptilimnium viviparum, above) is a perennial herb that grows to a height of 6 - 36 inches (in) (0.15 - 1.0 meter; m). The leaves are reduced to hollow, quill-like structures. The small, white flowers occur in heads, or umbels, reminiscent of a small Queen Anne's lace (Daucus carota) flower head. Flowers have five regular parts and are bisexual or unisexual, each umbel containing both perfect and male florets. Seeds are elliptical and laterally compressed, measuring 0.06 – 0.08 in (1.5 - 2.0 millimeters; mm) in length (Kral 1980, 1981). In pond habitats, flowering begins in May, while riverine populations flower much later, beginning in late June or July and continuing until frost.
Habitat: Harperella in North Carolina typically occurs on rocky or gravel shoals and sandbars and along the margins of clear, swift-flowing stream sections.
Distribution: Harperella is known from only two locations in North Carolina. One population occurs in the Tar River in Granville County. Another population was reintroduced to the Deep River recently after the original population known from that area disappeared. This population occurs in Chatham County, but the river serves as the divide between Chatham and Lee counties.
Threats: The primary threats to Harperella in North Carolina include changes in water flow and water quality. Because Harperella occupies a narrow range of water depths, changes in flow can destroy suitable habitat by inundation or persistent desiccation. Dams, reservoirs, or other water impoundments or diversions would almost certainly threaten nearby Harperella populations. Siltation caused by heavy construction, residential development, and agriculture has been cited as detrimental to the plant. Natural fluctuation in water flow causes significant yearly variation in subpopulation persistence. Small subpopulations are particularly susceptible to loss during normal high water events.
References:Buchanan, M.F. and J.T. Finnegan. 2010. Natural Heritage Program List of the Rare Plant Species of North Carolina. NC Natural Heritage Program, Raleigh, NC.
U.S. Fish and Wildlife Service. 1990. Harperella (Ptilimnium nodosum) Recovery Plan. Newton Corner, MA. 60 pp.
For More Information on Harperella...
- U.S. Fish and Wildlife Service Environmental Conservation Online System
- Harperella Recovery Plan
- U.S. Department of Agriculture Natural Resource Conservation Service Plants Database
- U.S. Forest Service Celebrating Wildflowers
- Center for Plant Conservation species profile
Dale Suiter, Fish and Wildlife Biologist, 919-856-4520 ext. 18
Species profile revised on July 26, 2011.