Medusahead (Taeniatherum caput-medusae)

Download 283K pdf file ("medusahead.pdf")PDF
     Subscribe to our free E-Newsletter, "Agri-News" (formerly RTW This Week)Agri-News
This Week
  Return to the Weed Information Home Page
Grows 15-45 cm tall, with a fibrous root. A narrow-leaved annual grass with long-awned spike inflorescence. Produces tillers, but very few narrow leaves. Spike inflorescence has stiff, long awns or bristles that can be 2-7cm long, finely barbed and can irritate mouths of livestock. Stems are hairy. Seed will twist as fruit matures, usually 7 seeds per spike.

Entire inflorescence falls, releasing seeds from within florets—does not break apart like foxtail barley. Spikelets are 2 per node. Lemma narrowly lanceolate, 3-veined, tapered into a straight to curved awn. Glumes awn-like also, 1-4 cm long, straight to slightly curved.

Key Identifiers
  • Medusahead matures 2-4 weeks later in the season than most other annual grasses
  • Seedlings remain attached to the long-awned florets
  • 3 veined lemmas
  • Main axis of flower spike does not break apart in fruit
  • Medusahead has 2 types of awns: both are flat, but the longer of the 2 contains barbs that point upward
  • awns are straight and compressed when green, becoming twisted and erratically spread upon drying

Steve Dewey, Utah State University,
Location in Canada
Reports have Medusahead in much of the western US and Canada. Reports in Alberta have not been made, to the best of my knowledge.

Resources Similar species
Unlike Medusahead, similar appearing Hordeum and Elymus species have 5-veined lemmas and main flower spike axes that typically break apart in fruit. In addition, Hordeum species have 3 florets per spikelet, with the lateral florets much smaller than the central floret.

Other Documents in the Series

  Jointed Goatgrass (Aegilops cylindrica)
Medusahead (Taeniatherum caput-medusae) - Current Document
Share via
For more information about the content of this document, contact Chris Neeser.
This document is maintained by Shelley Barkley.
This information published to the web on April 10, 2012.
Last Reviewed/Revised on August 21, 2018.