This plant guide identifies 23 noxious weeds that are known to occur on public land administered by the Bureau of Land Management's Alturas Field Office, located in northeastern California.  To view a photograph and more information on an individual plant, click on the plant's common name below.

Bull Thistle Cirsium vulgare	Canada Thistle Cirsium arvense	Musk Thistle Carduus nutans
Plumeless Thistle Carduus acanthoides	Scotch Thistle Onopordum acanthium	Wavyleaf Thistle Cirsium undulatum
Yellowspine Thistle Cirsium ochrocentrum	Yellow Starthistle Centaurea solstitialis	Diffuse Knapweed Centaurea diffusa
Russian Knapweed Acroptilon repens		Spotted Knapweed Centaurea maculosa
Squarrose Knapweed Centaurea sqarrosa	Common Crupina or Bearded Creeper Crupina vulgaris	Dyer's Woad or Marlahan Mustard Isatis tinctoria
Hoary Cress Cardaria draba	Perennial Pepperweed or Tall Whitetop Lepidium latifolium	Dalmatian Toadflax Linaria dalmatica
Halogeton Halogeton glomeratus	Klamathweed or St. Johnswort Hypericum perforatum	Leafy Spurge Euphorbia esula
Mediterranean Sage Salvia aethiopis	Purple Loosestrife Lythrum salicaria	Medusahead Taeniatherum caput      -medusae

Noxious weeds are non-native plants introduced to North America from Europe and Asia. These plants have spread at an alarming rate because, unlike native species, there are no native insects, fungi, or diseases to control their growth and spread in this country. What began as a handful of plants introduced in the 19th century, now number in the hundreds of millions. Noxious weeds destroy wildlife habitat and forage, threaten endangered species and native plants, increase erosion and groundwater loss and prevent recreational activities.

Estimates indicate that noxious weeds are spreading at rate of 4,600 acres per day on federal lands alone in the western United States.  They have invaded approximately 17 million acres of public rangelands in the West -- more than quadrupling their range from 1985 to 1995. In northern California, yellow starthistle expanded its range from 1 million acres in 1981 to 10 million acres in 1997.

The Bureau of Land Management is just one of many governement agencies mounting an effort to control and prevent noxious weeds, as well as educate the public about how destructive these plants can be.

The information presented here is from the book, Selected Noxious Weeds of Northeastern California, a joint project of the Bureau of Land Management, U.S. Forest Service, Lassen County, Modoc County, Northern Deputy Agricultural Commissioners and Sealers Association, Tuscarora Gas Transmission Company, and the California Department of Food and Agriculture.