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

USDA Code

TACA8

Legal Status

Colorado Noxious List A.

Not yet found in Colorado.

Identification

Lifecycle

Winter annual

Growth form

Grass. 6-24 in tall. Germinates in fall. Matures later than other annuals.

Flower

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.

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

Present throughout New Mexico and is reported in Arizona, California, Idaho, Montana, Nevada, Texas, Oregon and Washington (USDA Plant Database).

Historical

Western US.

General requirements

Native to Mediterranean region.

Biology/Ecology

Life cycle

Annual.

Mode of reproduction

Seed.

Dispersal

Animal, wind, water.

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.