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

USDA Code: TACA8

Legal Status: Colorado Noxious List A

IDENTIFICATION

Lifecycle: Winter annual

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

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

Seeds/Fruit: Awned-floret

Leaves: Slender, rolled, 1/8 inch wide

Stems: Slender, jointed.

Roots: Fibrous

Seedling: Yellow-green

SIMILAR SPECIES

Exotics: Seedlings similar to downy brome

IMPACTS

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

BIOLOGY/ECOLOGY

Life cycle: Annual

Mode of reproduction: Seed

Seed production:

Seed bank:

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

REFERENCES

Maurer, T., Russo M. J. (Revision), Godell A. (Revision); ELEMENT STEWARDSHIP ABSTRACT for Taeniatherum caput-medusae; http://tncweeds.ucdavis.edu/esadocs/documnts/taencap.pdf

The PLANTS Database, database (version 5.1.1) 2000; National Plant Data Center, NRCS, USDA. Baton Rouge, LA 70874-4490 USA. http://plants.usda.gov 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.