Phytolacca americana L.

Phytolacca americana L. – Poke (pokeweed)

Phytolaccaceae

Figure 1. Poke seed.

Poke seeds consistently, but infrequently, occur in archaeobotanical samples from the Eastern Woodlands. Their distinct appearance makes even fragmentary remains fairly easy to identify. Archaeological poke seeds have been assigned to various archaeobotanical categories due to the numerous uses of poke by historic groups.

Description

The seeds of poke are approximately 3 mm long, 2.5 mm wide, and 1.5 mm thick. They are lentil-shaped in cross-section and reniform or round in plan view. The rather thick testa is very shiny with no obvious testa patterning. The embryo encircles the endosperm, similar to the embryo in Chenopodium and Amaranthus spp. Poke seeds can be distinguished from these species based on poke’s larger size and lack of characteristic testa patterns. Also, uncarbonized poke seeds have a Y-shaped notch with a white plug that is not present on Chenopodium or Amaranthusspp. seeds (Asch and Asch 1977). See Figure 1 for illustration of poke seed.

Problems can arise in distinguishing modern poke seeds, which are shiny and black, from archaeological specimens. Archaeological seeds will be completely black with no reddish or brownish hue when viewed under magnification in bright light. If the archaeological seed is fragmented, then it will have no uncarbonized endosperm or inner seed coat layers; these are characteristic of modern seeds.

Archaeological Distribution

Poke seeds occur in a variety of archaeological contexts and periods. The berries were undoubtedly consumed in prehistory; five poke seeds were found in one of the Salts Cave paleofeces (Yarnell 1969:70). Carbonized seeds are occasionally found in Archaic through Mississippian contexts (Asch and Asch 1983; Chapman and Shea 1981).

Modern Distribution and Taxonomy

Phytolaccaamericana is the only member of the Phytolaccaceae family in North America. However, poke is widely distributed throughout the eastern half of the United States in areas with an average spring rainfall of greater than 20 cm and an average July temperature of less than 68 degrees F (Sauer 1948). Poke is almost exclusively associated with disturbed habitats including riverbeds, tree-fall areas, and areas opened due to human disturbance.

Poke plants are 0.6-3.6 m tall at maturity. The simple leaves have smooth margins and tend to be about 10 cm long. The greenish white sepals of the flowers are borne in loose terminal clusters and mature into drooping clusters of dark purple berries with red stems. Each fruit has six to twelve seeds. The fruits are persistent and must be transported from the mother plant by animal vectors. Poke is a perennial and large taproots are present in older plants. See Figure 2 for an illustration of the poke plant.

Figure 2. Poke plant (Gray 1860:191).

Discussion

Archaeological poke remains are often assigned to “weed seed” categories due to the plants aggressive colonization of open areas. However, such categorization does not exclude the possibility that wild poke was utilized by prehistoric people. There is ample evidence for use of poke by historic European and American Indian populations. The young leaves are a well-known edible pot herb. The fruits are probably edible after thorough cooking. The berries can also be used as a dye (although not color fast) or ink. The roots and berries have been used for a variety of medicinal purposes. Such potential economic uses should be included in interpretations of this plant in the archaeological record. All parts of the pokeweed contain phytolaccatoxin, a mitogen which can be absorbed through skin abrasions, and therefore the plant should be handled with care.

 

Written by: Michele Williams

References

  1. Asch D. L., and N. B. Asch
        1977   Chenopod as Cultigen. Mid-Continental Journal of Archaeology 2:3-45.
        1983   Archeobotany. In Excavations at the Smiling Dan Site, edited by B. D. Stafford and M. B. Sant, pp. 327-401. Research Series 2. Center for American Archaeology, Kampsville, Illiniois.
  2. Chapman, J. and A. B. Shea
        1981   The Archaeobotanical Record: Early Archaic Period to Contact in the Lower Little Tennessee RiverValley. Tennessee Anthropologist VI:61-84.
  3. Gray, A.
        1860   How Plants Grow. Ivison, Phimey and Company, New York.
  4. Sauer, J. D.
        1948   Poke (Phytolacca americana L.): Biology and Geography of a Weed. Unpublished Master’s thesis, Department of Biology, Washington University, St. Louis.
  5. Yarnell, R. A.
        1969   Contents of Human Paleofeces. In The Prehistory of Salts Cave, Kentucky, edited by P. J. Watson, pp. 41-53. Illinois State Museum Reports of Investigation No. 16. Springfield, Illinois.