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.
Coreopsis stillmanii is a species of flowering plant in the daisy family known by the common name Stillman's tickseed. It is endemic to California, where it grows in the Central Valley and most of the adjacent coastal and inland mountain ranges in California chaparral and woodlands habitats. It is found east of San Francisco Bay and on the eastern side of the Central Valley.
Coreopsis calliopsidea is a species of flowering plant in the daisy family known by the common name leafstem tickseed. It is endemic to California. The plant grows in some of the southern coastal mountain ranges and Transverse Ranges and the Mojave Desert from Alameda and Inyo Counties south to Riverside County.
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.
Cirsium andersonii is a North American species of thistle known by the common names Anderson's thistle and rose thistle. It is native to California, Oregon, and Nevada, where it grows in the woodlands and forest openings of the local high mountain ranges, including the Sierra Nevada and the southern Cascade Range. It has also been reported from Idaho.
Cirsium andrewsii is an uncommon species of thistle known by the common name Franciscan thistle. It is endemic to California, where it is known from the coastline of the San Francisco Bay Area from Marin to San Mateo Counties. There are also reports of isolated populations in the Klamath Mountains and in the Sierra Nevada.
Cirsium ciliolatum is a species of thistle known by the common name Ashland thistle. It is endemic to the Klamath Mountains, where it is known from only a few occurrences in Jackson and Josephine Counties in Oregon, as well as neighboring Humboldt and Siskiyou Counties in California. It is related to Cirsium undulatum and may be more accurately described as a variety of that species.
Cirsium crassicaule is a species of thistle known by the common name slough thistle. It is endemic to the San Joaquin Valley of California, where it is known primarily from freshwater wetlands. It has been found in only a few locations in Kern, Kings, and San Joaquin Counties.
Cirsium cymosum is a North American species of thistle known by the common name peregrine thistle. It is native to the western United States, where it has been found in California, Oregon, Nevada, Utah, Idaho, Wyoming, and Montana.
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 loncholepis is a rare species of thistle known by the common name La Graciosa thistle. It is endemic to California, where it is known from about 15 remaining occurrences in wetlands where southwestern San Luis Obispo County borders northwestern Santa Barbara County. It grows in coastal scrub and sand dunes, marshes, and moist grasslands in the watersheds of local rivers, including the Santa Maria River. It is a federally listed endangered species.
Cirsium mohavense is a species of thistle known by the common names virgin thistle and Mojave thistle. It is native to the southwestern United States, where it grows in moist areas in otherwise dry habitat, such as desert springs. It is most common in the Mojave Desert, found also in the southern Great Basin and other nearby regions of California, Nevada, western Arizona, and southwestern Utah.
Cirsium ochrocentrum is a species of thistle known by the common name yellowspine thistle. It is native to the Great Plains of the Central United States and to the desert regions of the western United States and northern Mexico. Its range extends from eastern Oregon east to the Black Hills of South Dakota, south as far as the Mexican State of Durango.
Cirsium rhothophilum is a rare North American species of thistle known by the common name surf thistle. It is endemic to California, where it is known only from the coastline around the border between San Luis Obispo and Santa Barbara Counties. It grows in sand dunes and coastal scrub near the beach.
Cirsium scariosum is a species of thistle known by the common names meadow thistle, elk thistle and dwarf thistle. It is native to much of western North America from Alberta and British Columbia south to Baja California. There are also isolated populations on the Canadian Atlantic Coast, on the Mingan Archipelago in Québec.
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.
Cirsium parryi, or Parry's thistle, is a species of North American flowering plants in the aster family. It is native to the southwestern United States, where it has been found in Colorado, Arizona, and New Mexico.
Cirsium repandum is a North American species of plants in the thistle tribe within the sunflower family. Common names include sand-hill thistle and coastal-plain thistle. The species is native to the southeastern United States, the coastal plain in Virginia, Georgia, and the Carolinas.
