Small-anthered Bittercress

Cardamine micranthera

Description

Small-anthered bittercress is a perennial mustard with an erect stem growing to a height of 7.8-15.6 in (20-40 cm). The short basal leaves have small rounded teeth and lateral lobes; the stem leaves are about 0.5 in (1 cm) long, alternate, mostly unlobed, and have rounded teeth. The four-petaled, white flowers bloom in April; the fruit is a silque (seed pod) about 0.4 in (1 cm) long.

Cardamine micranthera is distinguished from the closely related species, C. rotundifolia, by the size and shape of its anthers (nearly round), its erect growth form, and the smaller size of its silques.

Habitat

This species only grows in seepages, on stream banks, and in moist woods along a few streams in Stokes County, North Carolina, north of Winston-Salem.

Distribution

Small-anthered bittercress was first described in 1940. In the 1960s the only known population in Forsyth County was lost when the site was converted to a cattle pasture. Attempts to locate the known sites in Stokes County were unsuccessful, and the species was believed to be extinct.

In 1985, the species was rediscovered in Stokes County, and subsequent searches found three more populations. Three plants constitute the smallest population, while in the largest, about 200 plants, occurs along a stream bank. All four sites are located on private land.

Threats

The low number of existing small-anthered bittercress populations and the fact that the only sites are on private land puts the species at risk of extinction caused by logging or the conversion of its habitat to pasture. In addition, the species faces natural threats. One site is a midstream sandbar, which is vulnerable to flooding. At other sites the invasive Japanese honeysuckle (Lonicera japonica ) may eliminate the species.

Conservation and Recovery

The U. S. Fish and Wildlife Service published a Recovery Plan for the small-anthered bittercress in 1991. All of its surviving critical habitats are small, located on private land, and threatened by various development activities. These habitats should be protected by acquiring the land and designating ecological reserves, or by negotiating conservation easements with the landowners. The populations of the small-anthered bittercress should be monitored, and research undertaken into its biology, habitat needs, and beneficial management practices (including ways of reducing the abundance of invasive alien plants).

Contacts

U. S. Fish and Wildlife Service
Regional Office, Endangered Species
1875 Century Blvd., Suite 200
Atlanta, Georgia 30345
http://southeast.fws.gov/

U. S. Fish and Wildlife Service
Regional Office, Division of Endangered Species
300 Westgate Center Dr.
Hadley, Massachusetts 01035-9589
Telephone: (413) 253-8200
Fax: (413) 253-8308
http://www.northeast.fws.gov/

U. S. Fish and Wildlife Service
160 Zillicoa Street
Asheville, NC 28801-1082
Telephone: (828) 258-3939
Fax: (828) 258-5330

References

Cooper, J., S. Robinson, and J. Funderburg. 1977. Endangered and Threatened Plants and Animals of North Carolina: Proceedings of the Symposium on Endangered and Threatened Biota of North Carolina. State Museum of Natural History, Raleigh, North Carolina.

Leonard, S. 1986. "Pursuing the Small-Anthered Bittercress." North Carolina Wildflower Preservation Society, Spring Newsletter.

Radford, A., H. Ahles, and C. Bell. 1964. Manual of the Vascular Flora of the Carolinas. University of North Carolina Press, Chapel Hill.

U. S. Fish and Wildlife Service. 1991. "Small-anthered Bittercress Recovery Plan." Atlanta, Georgia.