Mohr's Barbara Button
Mohr's Barbara Button
|Listed||September 7, 1988|
|Description||Erect perennial herb with alternate leaves and pale pink to lavender flowers.|
|Habitat||Grassy glades within mixed hardwood forests.|
|Threats||Fire suppression, plant succession, habitat disturbance.|
Mohr's Barbara button (Marshallia mohrii ) is an erect perennial herb with stems 11.8-27.6 in (30-70 cm) tall, arising from a thickened stem base (caudex). Alternate lanceolate or ovate leaves are three-veined and 3-8 in (7.6-20.3 cm) long. Leaves decrease in size from the base to the top of the plant. Pale pink to lavender flowers, typically produced in several heads in a branched arrangement, bloom from mid-May through June. Fruits mature in July and August.
Mohr's Barbara button is found in moist, grassy openings in mature woodlands and beside shale-bedded streams. Soils are typically alkaline clays with a high admixture of organic matter. Various grasses and sedges are commonly associated with Mohr's Barbara button. Oaks and pines are predominant in the surrounding mixed hardwood woodland.
Two other federally listed species, Alabama leather flower (Clematis socialis ) and green pitcher plant (Sarracenia oreophila ), occur in the same habitat.
Mohr's Barbara button is endemic to the mountains of north-central Alabama (directly north of Birmingham), which stretch east into Georgia along the Appalachian range. The species was historically found in five Alabama counties (Bibb, Cherokee, Cullman, Etowah, and Walker) and a single Georgia county (Floyd).
As of 1992 a total of 22 sites were known for the species, including 15 populations in Alabama and seven in Georgia. When listed in 1988, the species was known at 13 sites in Alabama and one in Georgia. The largest populations are found in Cherokee County, Alabama, at two sites totaling some 1,000 plants; nearby are six smaller, satellite colonies. Etowah County records four populations, none numbering more than 200 plants. A single small population survives in Bibb County, according to a 1986 survey. A number of these sites are state-owned, with the rest being in private ownership. A remnant population was also known in Floyd County, Georgia, near the Alabama border.
As a result of surveys initiated in the summer of 1991, the Georgia Department of Natural Resources discovered an additional seven populations of Mohr's Barbara button in Floyd County, marking the first documented occurrence of the plant in that state since the early 1900s. The newly discovered populations range in size from 17-300 plants.
The U. S. Fish and Wildlife Service (FWS) 1991 Recovery Plan for this species estimated the existence of about 1,000 individuals growing at two sites; 12-50 individuals growing at seven sites; 100-200 individuals growing at six sites; 17-50 individuals at three sites; and 100-300 individuals at four sites.
Mohr's Barbara button has declined across its range because of loss of habitat due to suppression of fire and resulting natural vegetational succession. When fires are suppressed, the glades and grassy clearings within the forests are gradually overshadowed by the surrounding trees. This eventually shades out plants, like Barbara button, that require full sun.
When forest clearings disappear, this species survives in other cleared areas—along roadsides or in utility line corridors. These sites are vulnerable to ongoing maintenance activities such as mowing and herbicide application.
Although the flower is not currently valued as a commercial species, it possesses horticultural potential due to its aesthetic value. The plant is susceptible to taking and vandalism due to the accessibility of the sites where it grows and its visibility during flowering.
Conservation and Recovery
The Alabama Highway Department has been advised of the location of plants that occur along state highways and has agreed to modify its maintenance routines to benefit the plant. Because no plants are found on federal lands, further efforts to recover Mohr's Barbara button will depend on the cooperation of private landowners. To foster long-term survival of the plant, forested lands within the range will need to be managed by controlled burning or cutting to maintain habitable clearings.
The 1991 FWS Recovery Plan notes that the species will be considered for delisting when there are at least 15 viable populations and all are protected from human-related or natural threats. This can be accomplished by a number of specific goals, including: 1) protecting existing populations and habitat by contacting landowners and negotiating protection; 2) searching for additional populations; 3) determining population sizes, parameters for viable populations, and habitat characteristics; 4) conducting demographic studies and obtaining life history information by initiating demographic studies; 5) determining and implementing appropriate management by conducting management technique experiments, preparing individual site management plans, and implementing these plans; 6) conducting monitoring studies; and 7) preserving genetic stock by establishing a seed bank and maintaining material in cultivation.
U.S. Fish and Wildlife Service
Regional Office, Division of Endangered Species
1875 Century Blvd., Suite 200
Atlanta, Georgia 30345
Telephone: (404) 679-4000
Freeman, J. D. 1984. "Vascular Plant Species Critical to Maintenance of Floristic Diversity in Alabama." Report. U. S. Fish and Wildlife Service, Atlanta.
Kral, R. 1973. "Some Notes on the Flora of the Southern States, Particularly Alabama and Middle Tennessee." Rhodora 75: 366-410.
Kral, R. 1983. "Report on Some Rare, Threatened or Endangered Forest-Related Vascular Plants of the South." Technical Publication R8-TP2. USDA, Forest Service, Washington, D. C.
U. S. Fish and Wildlife Service. 1991. "Recovery Plan for Mohr's Barbara Button." U. S. Fish and Wildlife Service, Jackson, Miss.
Watson, L. E., and J. R. Estes. 1987. "Chromosomal Evolution of Marshallia [Asteraceae]." American Journal of Botany 74: 764.
Whetstone, R. D. 1979. "New or Noteworthy Records for Flora of Alabama." Castanea 44: 1-8.