Marshallia mohrii
Encyclopedia
Mohr’s Barbara Button, (Marshallia mohrii), is a perennial herb
Herb
Except in botanical usage, an herb is "any plant with leaves, seeds, or flowers used for flavoring, food, medicine, or perfume" or "a part of such a plant as used in cooking"...

 species, currently listed as threatened
Threatened species
Threatened species are any speciesg animals, plants, fungi, etc.) which are vulnerable to endangerment in the near future.The World Conservation Union is the foremost authority on threatened species, and treats threatened species not as a single category, but as a group of three categories,...

 on the Endangered Species List. It has been listed on the Endangered Species list since 1988. Mohr’s Barbara Button is found in the Southeastern United States
Southeastern United States
The Southeastern United States, colloquially referred to as the Southeast, is the eastern portion of the Southern United States. It is one of the most populous regions in the United States of America....

, in several locations in Alabama
Alabama
Alabama is a state located in the southeastern region of the United States. It is bordered by Tennessee to the north, Georgia to the east, Florida and the Gulf of Mexico to the south, and Mississippi to the west. Alabama ranks 30th in total land area and ranks second in the size of its inland...

 and Georgia
Georgia (U.S. state)
Georgia is a state located in the southeastern United States. It was established in 1732, the last of the original Thirteen Colonies. The state is named after King George II of Great Britain. Georgia was the fourth state to ratify the United States Constitution, on January 2, 1788...

. The first recorded discovery of the species was in 1882 by Dr. Charles Mohr, hence the name Mohr’s Barbara Button.

Physiology

Mohr’s Barbara Button grows to around 1-2.5 ft in height, with 2.5 cm wide tubular-shaped flowers found in 2-6 flower masses. The flowers can range in color from white, to pale pink or lavender. The leaves of the plant are lanceolate
Leaf shape
In botany, leaf shape is characterised with the following terms :* Acicular : Slender and pointed, needle-like* Acuminate : Tapering to a long point...

 to ovate in shape, ranging from 6-10 cm long and 2 cm wide, with three parallel veins. The leaves are larger and more numerous near the base of the stem. (Patrick, Krakow, 1995) The plant typically flowers from mid-May through June, with fruit being produced in July and August. (Tsao, Van Lonkhuyzen, 2000) The fruit is a 5-angled, 10-ribbed achene
Achene
An achene is a type of simple dry fruit produced by many species of flowering plants. Achenes are monocarpellate and indehiscent...

, about 4 mm long, with a hairy, resin-dotted surface. The fruit is topped by a crown (pappus
Pappus
Pappus may refer to:*Pappus , a type of flower structure*Pappus of Alexandria, Greek mathematician**Pappus's hexagon theorem, often just called 'Pappus's theorem', a theorem named for Pappus of Alexandria...

) of five, narrowly triangular, sharply pointed scales, which are 1-3 mm long. The fruits are found among the sharply pointed bracts
Bract
In botany, a bract is a modified or specialized leaf, especially one associated with a reproductive structure such as a flower, inflorescence axis, or cone scale. Bracts are often different from foliage leaves. They may be smaller, larger, or of a different color, shape, or texture...

 (chaff
Chaff
Chaff is the dry, scaly protective casings of the seeds of cereal grain, or similar fine, dry, scaly plant material such as scaly parts of flowers, or finely chopped straw...

), which persist on the flower head. (Patrick, Krakow, 1995)

Habitat

The Mohr’s Barbara Button requires wet, sandy clay soils, with alkaline pH
Alkali soils
Alkali, or alkaline, soils are clay soils with high pH , a poor soil structure and a low infiltration capacity. Often they have a hard calcareous layer at 0.5 to 1 metre depth. Alkali soils owe their unfavorable physico-chemical properties mainly to the dominating presence of sodium carbonate...

, and high organic matter. Most currently known populations occur on soils of the Conasauga-Firestone Association. (Alabama Power Company, 2007) This is typically found along shale-bedded streams, especially in seasonally moist forest gaps, and in low swales extending onto roadside rights-of-way. Mohr’s Barbara Button can survive in full sun or partial shade, often in association with grass-sedge communities. Two other endangered species have the same habitat requirements as the Mohr’s Barbara Button: The Alabama Leather-Flower and the Green Pitcher Plant are both listed as endangered, and occupy the same limited habitat. (Alabama Power Company, 2007)

Threats

Mohr’s Barbara Button suffers primarily from habitat loss due to residential development, road maintenance and enlargement, trash disposal, and to a small extent, agricultural development. Because the environments in which Mohr’s Barbara Button exists are typically alkaline, sandy soils, crop production is not typically favorable in these environments.

Although direct human destruction of habitat can be blamed for population declines, too much human influence in protecting it can be problematic as well. Fire suppression in the pine and oak forests of the southeast United States has also taken its toll on the Mohr’s Barbara Button. Although the species requires mature pine and oak forests to survive, without occasional fires, the glades and openings required by the species become overgrown with forest vegetation. Therefore the trees and habitat needed by the Mohr’s Barbara Button, and protected through fire suppression can become a major problem as well for the species. (Matthews, 1994)

Another risk many species face, especially plant species, is habitat fragmentation
Habitat fragmentation
Habitat fragmentation as the name implies, describes the emergence of discontinuities in an organism's preferred environment , causing population fragmentation...

. As habitat gets destroyed, it is common that individual populations get isolated from each other. As populations get isolated from each other, and members of differing populations cannot interact, the genetic variation
Genetic variation
Genetic variation, variation in alleles of genes, occurs both within and among populations. Genetic variation is important because it provides the “raw material” for natural selection. Genetic variation is brought about by mutation, a change in a chemical structure of a gene. Polyploidy is an...

 within populations starts to decrease. If populations are not able to interact for many generations, a loss of genetic diversity with populations, and the species as a whole become a very real problem. Luckily, habitat fragmentation and a lack of genetic variation is not a problem for Mohr’s Barbara Button, as the species has more variation than most others in its environment. Also, the genetic variation within populations is greater than amongst populations. (Jolls)

Methods to protect the species

There are many stakeholders involved in protecting the Mohr’s Barbara Button. The calcareous glades
Calcareous grassland
Calcareous grassland is an ecosystem associated with thin basic soil, such as that on chalk and limestone downland. Plants on calcareous grassland are typically short and hardy, and include grasses and herbs such as clover...

 necessary for the survival of Mohr’s Barbara Button used to be fairly common and widespread. Currently, the remaining areas predominantly exist on private land, with none on federally protected land. Therefore landowners are one of the most important stakeholders involved. But, government and private organizations in charge of protecting plant species need to educate and work with private landowners to ensure the protection and survival of the habitat required for Mohr’s Barbara Button.

Government organizations are also necessary to protect habitat, as road construction and urban development is a major cause of habitat destruction. Therefore, an adequate examination of the land should occur prior to zoning, construction and/or development. Also, even if the land is safe from construction or development, it has to be protected from the effects of human population. Garbage and waste disposal can pollute and destroy critical habitat, as well as over-use by grazing livestock.

Presently, the Nature Conservancy has purchased several areas with calcareous glades and marly prairies, to ensure the survival of the Mohr’s Barbara Button and those endangered species that occupy the same habitat. They are also working with landowners to protect those areas that are found on private land. (Schotz, 2001) Through habitat protection by private and public sectors, the Mohr’s Barbara Button and other endangered species can survive and flourish for future generations.

Because some populations have become established in road right-of-ways and ditches, it is important to check road ditches before mowing or construction. This ensures no populations that have established in road right-of-ways are destroyed. Simply not mowing an area of roadside will not detract from the aesthetics of an area, and will protect valuable individuals/populations.

Reasons to protect the Mohr’s Barbara Button

The Mohr’s Barbara Button is a wildflower native to the United States. Protecting habitat does not require setting aside large tracts of valuable land. The land its habitat primarily occupies is low in value, and not highly desired for agricultural production.

Since the Mohr’s Barbara Button is a plant, it cannot migrate to another area that is more suitable, or safer. For this reason, Mohr’s Barbara Button, as with most plants, is susceptible to major population loss due to habitat degradation or destruction. Therefore humans need to protect the environments these plants require to survive. Since Mohr’s Barbara Button has a very distinct and limited habitat, it is vital to protect these habitats as a whole, as they are important to several other threatened and endangered species as well.

Sources

  • Tsao, C. L. and Van Lonkhuyzen, R. 2000. Final Biological Impact Statement For Anniston Army Depot. Argonne National Laboratory, Argonne, Illinois.
  • Schotz, A. R. 2001. Threatened and Endangered Species: Mohr’s Barbara Button. Alabama’s TREASURED Forests.
  • Jolls, C. L. 2003. Populations of and Threats to Rare Plants of the Herb Layer. Page 108 in F. Gilliam and M. Roberts, editors. The Herbaceous Layer in Forests of Eastern North America. Oxford University Press, United States.
  • Alabama Power Company. 2007. Biological Assessment for Threatened and Endangered Species for the Coosa River (FERC NO. 2146), Mitchell (FERC NO. 82), and Jordan (FERC NO. 618) Projects. Alabama Power Company, Birmingham, Alabama.
  • Matthews, J.R. 1994. The Official World Wildlife Fund Guide to Endangered Species. Vol I. pp. 273-274. Beacham Publishing Inc. Washington, DC.
  • Newcomb, L. 1989. Newcomb's Wildflower Guide: An Ingenious New Key System for Quick, Positive Field Identification of the Wildflowers, Flowering Shrubs and Vines of N, Vol. 1. Little, Brown & Company Publishing.
  • Horn, D. Hemmerly, T. Cathcart, T. Duhl, D. 2005. Wildflowers of Tennessee, the Ohio Valley and the Southern Appalachians. Lone Pine Publishing.
  • Environmental Protection Agency. Pesticides: Endangered Species Protection Program. http://epa.gov/espp/alabama/cherokee.htm Viewed March 31, 2008.
  • Patrick, Allison and Krakow. 1995, Protected Plants of Georgia, Georgia Department of Natural Resources
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