PO Box 364

Paonia, CO 81428



fax: 720-880-3051




Taeniatherum caput-medusae


Keys to Identification

  • An aggressive winter annual grass
  • The 4 inch inflorescence persists after the plant has matured

Family: Poaceae (Grass)


Other Names: medusahead rye




Legal Status: Colorado Noxious List A

Not yet found in Colorado.


Photo: Sue Donaldson, UNCE




Lifecycle: Winter annual


Growth form: Grass. 6-24 inches tall. Germinates in fall. Matures later than other annuals.


Inflorescence: Long-awned spike. Head persists after seed fall. Awns are twisted, stiff when mature. May-June.


Seeds/Fruit: Awned-floret


Leaves: Slender, rolled, 1/8 in wide


Stems: Slender, jointed.


Roots: Fibrous


Seedling: Yellow-green



Similar Species

Exotics: Seedlings similar to downy brome




Agricultural: Unpalatable to livestock when mature. Aggressive. Degrades rangelands. Builds up duff layer that ties up nutrients and may contribute to fire


Ecological: Degrades natural lands



Habitat and Distribution

General requirements: Semi-arid clay soils


Distribution: Western US


Historical: Native to Mediterranean region




Life cycle: Annual


Mode of reproduction: Seed


Dispersal: Animal, wind, water



Integrated Management Summary

Burning will remove the thick duff layer.


Early grazing may provide some control.


Herbicide treatments are most effective.




Maurer, T., Russo M. J. (Revision), Godell A. (Revision); ELEMENT STEWARDSHIP ABSTRACT for Taeniatherum caput-medusae;


The PLANTS Database, database (version 5.1.1) 2000; National Plant Data Center, NRCS, USDA. Baton Rouge, LA 70874-4490 USA. Reference for: Taeniatherum caput-medusae


Whitson, T.D.(ed.), L.C. Burrill, S.A. Dewey, D.W. Cudney, B.E. Nelson, R.D. Lee, R. Parker. 2001. Weeds of the West. Western Society of Weed Science, in cooperation with the Western United States Land Grant Universities Cooperative Extension Services, Newark CA. pg. 493.


Back to Weed List