Echinochloa muricata (P. Beauv.) Fern

Barnyard grass.

Poaceae (Graminae)

       Barnyard grass is one of the grass species with small, rounded seeds that are often found in fine fractions from floated archaeobotanical samples. Archaeobotanists in eastern North America were not sure about the precise identification of these starchy seeds, and therefore tentatively labeled them Gramineae or Poaceae Type 6F. The grass seeds Type 6F were later identified to the genus Echinochloa (Asch and Asch 1985) and more recently to the species Echinochloa muricata var. microstachya Wieg. (Steyermark includes var. occidentalis Weig.; Mohlenbrock includes var. wiegandii Fassett) (Hunter 1990).

Description
       The caryopses (grains) of Echinochloa muricata var. microstachya are circular to broadly oval in shape. Dimensions range from ca. 1.2 mm (diameter) x 0.6 mm (thickness). Although sometimes mislabeled as ventral, the dorsal side of the caryopsis (Figure 1) is slightly convex and bears an embryo. The embryo is preserved on some archaeological specimens, but is often lacking, leaving a distinctive radicle depression which is also called a scutellum groove. The radicle depression extends almost to the apex of the caryopsis.  The sides of the radicle depression are almost parallel. The ventral side of the caryopsis is flat (Figure 2).  The small circular hilum (point of attachment of the grass grain to palea) is observable towards the base of the caryopsis on the ventral side as a dark rounded dot on modern specimens, and only as a small circular depression on the carbonized ones. Longitudinal lines on the surface a seed could be observed on a few carbonized specimens on which remnants of lemma and palea were still preserved. These specimens exhibit sharp pointedness of the apex (Hunter 1990:202). Also, cereal grains that are tightly enclosed in lemma and palea, as in the case of Echinochloa and Panicum, exhibit great variation in overall shape of the seeds after carbonization.

Archaeological Distribution
       Johannessen (1983a) and several other archaeobotanists identified Gramineae (Poaceae) Type 6F seeds at Late Archaic, Woodland, and many Mississippian sites excavated during the FAI-270 Project in the American Bottom area. Also, 69 seeds of Echinochloa were identified by Asch and Asch (1985) at the Late Mississippian Hill Creek site in Illinois. At this site and several others, E. muricata (Gramineae Type 6F) often occurs in archaeological assemblages together with Gramineae Type 6L seeds which are identified as panic grass (see entry on Panicum sp.), and also with Gramineae Type 20/21 seeds which are identified as little barley (Hordeum pusillum Nutt.). Furthermore, Hunter (1990) identified 71 seeds of E. muricata from the Tremaine site in Wisconsin, dated to the Oneota Period. She had done extensive research on Type 6F grass seeds and cites most of the references and the sites where these seeds have been identified.

The Modern Plant and Its Distribution
       Plants of genus Echinochloa are cosmopolitan species found throughout the USA in a variety of habitats, and its greatest abundance is actually in eastern central North America. Echinochloa species are most commonly found in wet habitats, near the water, especially on mud flats from which water has receded early in growing season (Martin et al. 1951:442). E. muricata also appears in waste land and as a weed in gardens. Most of the identified seeds from archaeological assemblages come from sites near the water where occasional floods were and are quite common.

Discussion
       Johannessen (1983b:105) suggested that Gramineae Type 6F seeds could belong to Setaria sp., possibly to S. geniculata (Lam.) Beauv. However, Hunter (1990) excluded this possibility on the basis of the overall shape and dimensions, and the length of the radicle depression. Seeds of Setaria species are slightly more elongated, and many species have observable transverse wrinkles on the lemma which are lacking from the Gramineae Type 6F. Also, the hilum on the ventral side of Setaria species is not circular in shape, but rather oval and twice as long as wide. Asch and Asch (1985:157) appear to have been the first to identify this archaeobotanical seed type as a member of the genus Echinochloa. Those authors discussed the possibility that the grains could be identified as E. pungens (Poir.) Rydb., which is one of the indigenous species in Illinois. They also mention that this species appears in Missouri (Steyermark 1963:234) under the synonym E. muricata. Hunter (1990) later identified the variety of Gramineae Type 6F as E. muricata var. microstachya. She eliminated E. muricata var. muricata (Steyermark includes var. ludoviciana Wieg.) on the basis of slightly different dimensions. E. muricata was classified earlier as E. crusgalli (L.) P. Beauv. or E. pungens by some taxonomists, and according to Hitchcock (1950:712), identification of these living plants could sometimes be only arbitrarily distinguished.

       Asch and Asch (1985) suggested that barnyard grass plant was used for thatching, pit lining and matting, and they classify the Echinochloa seeds in their category of "technological seeds." However, it should be noted that the authors did not exclude the potential use of these seeds as food. Furthermore, they cite ethnohistoric evidence described by Fernald and Kinsey (1958:105) that the grains of Echinochloa were abundant and easily obtained and that the seeds were worth the attention of the wild-food harvesters (Asch and Asch 1985:157). Ethnohistoric accounts mention that some western Indians used Echinochloa seeds as a food in the form of starchy flour from which they made breads or mush (Palmer 1878:602-603).  Husks needed to be either parched or beaten and later winnowed in order to release the seeds from the lemma and palea so that they can be ground into flour. Therefore, on the basis of the archaeological and ethnohistoric evidence, Hunter (1990) suggests that Echinochloa muricata var. microstachya should be reconsidered as a potential food resource. Seeds of the Echinochloa species are also important food for waterfowl species.

References
Asch, N. B., and D. L. Asch
    1985   Archaeobotany. In The Hill Creek Homestead and the Late Mississippian Settlement in the
            Lower Illinois Valley, edited by M. D. Conner, pp. 115-170. Center for American Archaeology
            Research Series, Vol. 1. Kampsville, Illinois.
Fernald, M. L., and  A. C. Kinsey
    1958   Edible Plants of Eastern North America. Harper and Row, New York.
Hitchcock, A. S.
    1950   Manual of Grasses of the United States. United States Department of Agriculture, Miscellaneous
            Publications 200.
Hunter, A. A.
    1990   Analysis of Floral Remains from the 1987 Excavations at Tremaine. In Prehistoric Sites in
            Lacrosse County, Wisconsin, by J. T. Penman and K. Hamilton, pp. 198-224. Wisconsin
            Department of Transportation, Archaeological Report 17. Madison, Wisconsin.
Johannessen, S.
    1983a  Plant Remains. In Robinson's Lake Site (11-Ms-582), by G. R. Milner, pp. 124-132. American
            Bottom Archaeology, FAI-270 Site Reports, Vol. 10. University of Illinois Press, Urbana.
    1983b  Floral Remains. In The Range Site: Archaic through Late Woodland Occupations (11-S-47), by
            J. K. Kelly, A. C. Fortier, S. J. Ozuk, and J. A. Williams, pp. 102-105. American Bottom
            Archaeology, FAI-270 Site Reports, Vol. 16. University of Illinois Press, Urbana.
Martin, A. C., H. S. Zim, and A. L. Nelson
    1951   American Wildlife and Plants: A Guide to Wildlife Food Habits. Dover Publications, New York.
Palmer, E.
    1878   Plants Used by the Indians of the United States. American Naturalist 12:593-606.
Steyermark, J. A.
    1963   Flora of Missouri. Iowa State University, Ames.

Written by: Ksenija Borojevic