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Scientific Name:
Cynoglossum officinale L. (ITIS)
Common Name:
Houndstongue, gypsy flower, rats and mice, dog bur
Houndstongue, flowers - Photo by Mary Ellen (Mel) Harte
Native To:
Date of U.S. Introduction:
First discovered in 1893 (Kedzie-Webb and Sheley 2017)
Means of Introduction:
Introduced accidentally through contaminated seed (Kedzie-Webb and Sheley 2017)
Infests pasture and rangeland, where it is toxic to livestock (Kedzie-Webb and Sheley 2017)

Distribution/Maps/Survey Status


Selected Resources

The section below contains selected highly relevant resources for this species, organized by source. To view all related content for this species, click on "View all resources for species" in the top left of this page.

Council or Task Force

Alberta Invasive Species Council (Canada).
See also: Fact Sheets for more information about individual invasive species, including those listed as "Prohibited Noxious" and "Noxious" under the Alberta Weed Control Act


IUCN. Species Survival Commission. Invasive Species Specialist Group.
University of Georgia. Center for Invasive Species and Ecosystem Health.

Federal Government

USDA. FS. Rocky Mountain Research Station. Fire Sciences Laboratory.
USDA. NRCS. National Plant Data Center.
USDA. ARS. National Genetic Resources Program. GRIN-Global.

State and Local Government

Oregon Department of Agriculture. Plant Division. Noxious Weed Control.

See also: Oregon Noxious Weed Profiles for more species
Washington State Noxious Weed Control Board.
King County Department of Natural Resources (Washington). Water and Land Resources Division.
Colorado Department of Agriculture. Conservation Services Division. Noxious Weed Program.


North Dakota State University. Extension Service.
Utah State University. Extension.
University of California. Weed Research and Information Center.
See also: Weeds in Natural Areas for more information sheets


Colorado Weed Management Association.
Montana Weed Control Association.