Maygrass or Reed Canary Grass

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Maygrass (Phalaris caroliniana Walter)

Maygrass is an annual native grass found throughout the southern U.S. It is a winter annual with starchy seeds that ripen in May and June. Maygrass seeds are difficult to distinguish from a closely related perennial, reed canary grass (Phalaris arundinacea). Reed canary grass is indigenous to Iowa while maygrass is not. Most archaeological discoveries found in Iowa are considered likely to represent cultivated maygrass rather than reed canary grass.

Maygrass seeds found in paleofeces from dry caves in Kentucky directly demonstrate that the plant was part of the prehistoric diet. The seeds are high in carbohydrates, low in fat, and a rich source of dietary iron and thiamin. It has a higher protein content than other starchy and oily seeded plants and nuts used by Woodland peoples. Like other starchy-seeded plants, maygrass was probably prepared by parching and boiling. The seeds may also have been ground.

Maygrass first occurs in Late Archaic sites dating 2,000—3,000 years old. In Iowa cultivated maygrass appears in 2,000 year old Middle Woodland contexts at sites like Gast Farm (13LA12) and Sand Run West (13LA38.) It was cultivated into the late prehistoric period.

Major References

Asch, David and William Green 1992
Crites, Gary D. and R. Dale Terry 1984
Green, William and Shelly Gradwell 1995

Map of Iowa with fuschia dots that indicate prehistoric sites known to have cultivated maygrass

Iowa Sites
Site Number Major Reference Family Genus and Species Iowa Culture
13AM403 Powell, 2005 GRAMINEAE or POACEAE Phalaris caroliniana O
13BV1 Jones, 1993 GRAMINEAE or POACEAE Phalaris caroliniana MC
13CK15 Jones, 1993 GRAMINEAE or POACEAE Phalaris caroliniana MC
13DA264 Asch, 1996 GRAMINEAE or POACEAE Phalaris sp. GO
13LA1 Hollinger, 1999; 2005 GRAMINEAE or POACEAE Phalaris sp. O
13LA12 Dunne, 2002; Hodgson, 1992 GRAMINEAE or POACEAE Phalaris sp. MW/ELW
13LA38 Asch and Green, 1992 GRAMINEAE or POACEAE Phalaris caroliniana MW/LW
13LA309 Powell, 2001 GRAMINEAE or POACEAE Phalaris caroliniana LW
13LE110 Zalucha, 1999 GRAMINEAE or POACEAE Phalaris sp. MLW
13LE117B Zalucha, 1999 GRAMINEAE or POACEAE Phalaris sp. ELW
13WD88 Dunne, 2005 GRAMINEAE or POACEAE Phalaris sp. GO

 

Key
MW Middle Woodland
ELW Early Late Woodland
MLW Middle Late Woodland
LW Late Woodland
GO Great Oasis
MC Mill Creek
O Oneota

Two photographs of maygrass

Two photographs of maygrass

 

Image credit:
Larry Allain @ USDA-NRCS PLANTS Database
Melanie Riley and Mary Kathryn Rocheford, OSA (map)