Maygrass or Reed Canary Grass


Table of Contents

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 NumberMajor ReferenceFamilyGenus and SpeciesIowa Culture
13AM403Powell, 2005GRAMINEAE or POACEAEPhalaris carolinianaO
13BV1Jones, 1993GRAMINEAE or POACEAEPhalaris carolinianaMC
13CK15Jones, 1993GRAMINEAE or POACEAEPhalaris carolinianaMC
13DA264Asch, 1996GRAMINEAE or POACEAEPhalaris sp.GO
13LA1Hollinger, 1999; 2005GRAMINEAE or POACEAEPhalaris sp.O
13LA12Dunne, 2002; Hodgson, 1992GRAMINEAE or POACEAEPhalaris sp.MW/ELW
13LA38Asch and Green, 1992GRAMINEAE or POACEAEPhalaris carolinianaMW/LW
13LA309Powell, 2001GRAMINEAE or POACEAEPhalaris carolinianaLW
13LE110Zalucha, 1999GRAMINEAE or POACEAEPhalaris sp.MLW
13LE117BZalucha, 1999GRAMINEAE or POACEAEPhalaris sp.ELW
13WD88Dunne, 2005GRAMINEAE or POACEAEPhalaris sp.GO


MWMiddle Woodland
ELWEarly Late Woodland
MLWMiddle Late Woodland
LWLate Woodland
GOGreat Oasis
MCMill Creek

Two photographs of maygrass

Two photographs of maygrass


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