Elymus caput-medusae

Elymus caput-medusae_medusahead_Bob Case_cropped
Photo: Bob Case

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. Medusahead 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?

CDFA Rating: -*?


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.

Species ID Card

Invasive Species ID Card - To support field identification of early detection species, Cal-IPC has designed a set of Species ID cards that can be downloaded, printed double-sided, and trimmed to size.

Special Reports

Medusahead Management Guide for the Western States

Weed 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

  • Bugwood - National database from the Center for Invasive Species and Ecosystem Health at the University of Georgia.
  • CalPhotos - Images of plants taken mostly in California.
  • Calflora - Distribution map and records of this species in California.
  • EDDMapS - Distribution of this species in North America.
  • Jepson Interchange - Information on this plant's taxonomy, biology, and distribution from UC Berkeley's Jepson Herbarium.
  • USDA PLANTS Database - Information on identification and distribution, with links to websites in individual states.
  • Additional photos

    Elymus caput-medusae_flower spikes_copyright 2016_NealKramer
    Elymus caput-medusae (medusahead) flower spikes. Photo: &#169 2016 Neal Kramer
    Elymus caput-medusae_medusahead_Bob Case_cropped
    Elymus caput-medusae (medusahead) infestation. Photo: Bob Case