PO Box 419

Hotchkiss, CO 81419



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: Grass (Poaceae)


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 in 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.





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.


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