Panax quinquefolius L.
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Basis for Listing
Panax quinquefolius is a perennial herb native to hardwood forests in eastern North America. It is closely related to the Asian P. ginseng, which has been a staple in indigenous folk medicine in Asia for centuries. As P. ginseng became overexploited and scarce in Asia, it created an export market for the American P. quinquefolius. Beginning in the colonial era, thousands of tons of dried P. quinquefolius root were exported to Asia. These were the roots of wild plants that were taken from native forests at unsustainable levels. It did not take long for P. quinquefolius to become scarce in the eastern United States. When settlers moved westward into Minnesota, they found P. quinquefolius to be very common here. In fact, it was reported to carpet the forest floor over vast areas. Settlers did not hesitate to dig and sell the roots, repeating the pattern that was established farther east. As P. quinquefolius became scarcer, the price increased, reflecting the diminishing supply. The increased price only served to increase the intensity of exploitation, a cycle that has continued to this day.
Panax quinquefolius is an erect, perennial, forest herb with a single stem 20-61 cm (8-24 in.) tall. At the top of the stem is a whorl of 1-4 leaves; each leaf is palmately divided into 3-5 stalked leaflets. Each leaflet is obovate in shape, has a toothed margin, and a narrowly pointed tip. The small, greenish flowers are arranged in a solitary stalked umbel that rises above the leaves. In late summer, the umbel produces a cluster of red, berrylike fruits. The palmate pattern of leaflets is similar to the woody vine Parthenocissus vitacea (woodbine), which often occurs in the same habitat. Another associated species is the closely related Aralia nudicaulis (wild sarsaparilla), which differs by having pinnately divided leaves.
Wild P. quinquefolius grows only in well-developed forest soil, typically mesic loamy soil. In most cases, the forests have a closed canopy of mature Acer saccharum (sugar maple), Tilia americana (basswood), or Quercus rubra (red oak). Panax quinquefolius does not tolerate habitats that are seasonally flooded, such as might be found along a stream or river, or the edge of a marsh.
Biology / Life History
Panax quinquefolius is a long-lived, perennial herb that reproduces only by seeds that germinate after 2 winters in the soil. The seedling usually has 1 leaf with 3 leaflets. In each successive year, the plant will produce progressively more leaves, and the leaves will produce more leaflets. A healthy, mature individual will ultimately have 3 leaves, each with 5 leaflets. Occasionally plants with 4 leaves are found, but this is quite rare in the wild. Once a plant reaches the 2-leaf stage, it is capable of producing flowers. Depending on local conditions, a plant at this stage will usually flower every year. As the plant gets older and larger, it can be expected to produce more flowers and more fruits. It typically takes a plant 10 years or more to reach maximum size, depending on soil conditions, weather, herbivory, or other environmental factors. The age of a plant's roots can be determined with a fairly high degree of accuracy - at least a minimum age - by counting the leaf scars on the rhizome. One leaf is produced each year, so the number of leaf scars closely corresponds to the age of the plant in years. Although the older parts of a rhizome are often broken or worn, it is not unusual to find roots with rhizomes that show 40 to 50 or even 60 leaf scars.
Conservation / Management
Evidence from presettlement and early settlement records indicates that P. quinquefolius was very abundant in forests of southern Minnesota, thereby indicating that recovery may be achieved by controlling harvest pressure. It must be clearly stated that the root of the plant is what is harvested, not the leaves or stems. Therefore, when harvest takes place, the entire plant is killed. There is reason to believe that if only reproducing plants are taken, and if the seeds of the taken plant are put in the ground at the site of the parent plant (as the law requires), then harvesting at some level may be sustainable; this was clearly the intent of the law. However, populations are currently so depleted, and patches of habitat are so fragmented, that populations may not be able to adequately recover without further restrictions on harvest. An educational booklet has been developed for collectors in an effort to assure the future of wild ginseng in Minnesota.
Conservation Efforts in Minnesota
The export of P. quinquefolius roots is regulated by the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) as an Appendix II species. Under the terms of CITES, the interstate and international trade in P. quinquefolius is strictly controlled by the U.S. Fish and Wildlife Service. Continued approval for export from individual states is based on a determination by the U.S. Fish and Wildlife Service that exports will not be detrimental to the survival of the species. Ginseng harvest in Minnesota is further regulated under Minnesota Rules, Chapter 6282.
Cruse-Sanders, J. M., and J. L. Hamrick. 2004. Genetic diversity in harvested and protected populations of wild American ginseng, Panax quinquefolius L. (Araliaceae). American Journal of Botany 91:540-548.
Cruse-Sanders, J. M., and J. L. Hamrick. 2004. Spatial and genetic structure within populations of wild American ginseng (Panax quinquefolius L., Araliaceae). Journal of Heredity 95(4):309-321.
Grubbs, H. J., and M. A. Case. 2004. Allozyme variation in American ginseng (Panax quinquefolius L.): Variation, breeding system, and implications for current conservation practice. Conservation Genetics 5(1):12-23.
Lewis, W. H., and V. E. Zenger. 1982. Population dynamics of the American Ginseng Panax quinquefolium (Araliaceae). American Journal of Botany 69(9):1483-1490.