Elymus caput-medusae

Photo courtesy Joseph DiTomaso

Synonyms: Taeniatherum caput-medusae

Common names: medusahead

Elymus caput-medusae (medusahead) is a winter annual (family Poaceae) that typically invades disturbed sites, grasslands, openings in chaparral and oak woodlands. Taeniatherum caput-medusae out-competes native grasses and forbs and is found throughout northwestern California. After they set seed, medusahead plants persist as a dense litter layer that prevents germination and survival of native species, ties up nutrients, and contributes to fire danger in the summer.

Cal-IPC Rating: High

Cal-IPC Assessment

Plant Assessment Form - Information gathered by Cal-IPC on the impacts, rate of spread, and distribution of invasive plants in California. Does not include management information.

Special Reports

Medusahead Management Guide for the Western States

Weed RIC Management Notes

  • Management Notes - Information on management techniques and effectiveness from the University of California Cooperative Extension’s Weed Research & Information Center.

Cal-IPC Newsletter Articles

Cal-IPC Symposium Presentations

Presentations are linked where available. Where a presentation is not available, find more information by reading the abstract in the Cal-IPC Symposia Archive.

Other Elymus caput-medusae Information

  • CalPhotos - Images of plants taken mostly in California.
  • Calflora - See the distribution of this species on Calflora's map of California.
  • Jepson Online Interchange for California Flora - Information on taxonomy, biology, and distribution from UC Berkeley's Jepson Herbarium.
  • CDFA - California official noxious weeds.
  • USDA PLANTS Database - Federal database with information on identification and distribution, and links to websites in individual states.
  • Bugwood - National database from the Center for Invasive Species and Ecosystem Health at the University of Georgia.