Cirsium vulgare, the spear thistle, bull thistle, or common thistle, is a species of the Asteraceae genus Cirsium, native throughout most of Europe, Western Asia, and northwestern Africa. It is also naturalised in North America, Africa, and Australia and is an invasive weed in some areas. It is the national flower of Scotland.
Cirsium palustre, the marsh thistle or European swamp thistle, is a herbaceous biennial flowering plant in the daisy family, Asteraceae.
Cirsium oleraceum, the cabbage thistle or Siberian thistle, is a species of thistle in the genus Cirsium within the sunflower family, native to central and eastern Europe and Asia, where it grows in wet lowland soils.
Cirsium arvense is a perennial species of flowering plant in the family Asteraceae, native throughout Europe and northern Asia, and widely introduced elsewhere. The standard English name in its native area is creeping thistle.
Thistle is the common name of a group of flowering plants characterised by leaves with sharp prickles on the margins, mostly in the family Asteraceae. Prickles occur all over the plant – on the stem and flat parts of leaves. They are an adaptation that protects the plant from being eaten by herbivores. Typically, an involucre with a clasping shape of a cup or urn subtends each of a thistle's flowerheads.
Cirsium edule, the edible thistle or Indian thistle, is a species of thistle in the genus Cirsium, native to western North America from southeastern Alaska south through British Columbia to Washington and Oregon, and locally inland to Idaho.
Cirsium arizonicum, the Arizona thistle, is a North American species of thistle in the sunflower family, native to the southwestern United States and northwestern Mexico. It has been found in Arizona, southeastern California, New Mexico, Nevada, Colorado, Utah, Sonora, and northwestern Chihuahua.
Cirsium neomexicanum is a North American species of thistle known by the common names New Mexico thistle, powderpuff thistle, lavender thistle, foss thistle and desert thistle.
Cirsium occidentale, with the common name cobweb thistleor cobwebby thistle, is a North American species of thistle in the sunflower family.
The Blue Oak Ranch Reserve, a unit of the University of California Natural Reserve System, is a ecological reserve and biological field station in Santa Clara County, California. It is located on 3,260 acres (13.2 km2) in the Diablo Range, northwest of Mount Hamilton, at 1,500 ft (460 m) elevation.
Cirsium brevistylum is a species of thistle known by the common names Indian thistle and clustered thistle. It is native to western North America having been found in southwestern British Columbia, Washington, Oregon, Idaho, Montana, and California.
Cirsium douglasii is a species of thistle known by the common names Douglas' thistle and California swamp thistle.
Cirsium hydrophilum is a species of thistle which is endemic to California, where it is found only in the San Francisco Bay Area and the Sacramento-San Joaquin River Delta. This native thistle grows in wet boggy habitats.
Cirsium undulatum is a species of thistle known by the common names wavyleaf thistle and gray thistle. It is native to much of central and western North America from British Columbia east to Manitoba and south as far as the State of Durango in Mexico. It has also been found outside of its native range as an introduced species.
Trichosirocalus horridus is a species of true weevils, native to Europe. It is a biological pest control agent that was introduced into the United States in 1974 to control exotic thistles, especially in the Cirsium and Carduus genera.
Cirsium muticum, also known as swamp thistle, marsh thistle, dunce-nettle, or horsetops, is a North American species of plants in the sunflower family, native to central and eastern Canada and the central and eastern United States.
