(M.E. Jones) Petrak
Identity
Unique IDELEMENT_GLOBAL.2.883773
Element CodePDAST2E3R0
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryVascular Plant
Endemicendemic to a single nation
KingdomPlantae
PhylumAnthophyta
ClassDicotyledoneae
OrderAsterales
FamilyAsteraceae
GenusCirsium
Concept ReferenceFlora of North America Editorial Committee (FNA). 2006a. Flora of North America north of Mexico. Vol. 19. Magnoliophyta: Asteridae, part 6: Asteraceae, part 1. Oxford University Press, New York. xxiv + 579 pp.
Taxonomic CommentsCirsium clavatum of FNA (vol. 19, 2006) includes the following species that are separately recognized by Kartesz 1999: C. araneans and C. osterhoutii (in C. clavatum var. osterhoutii), C. griseum, C. laterifolium, C. modestum, and C. scapanolepis (in C. clavatum var. americanum).
Conservation Status
Edition Date1993-09-24
Edition AuthorsStoner, N.; Rev. C. Annable, rev. J. Beckman (3/96)
Threat ImpactMedium
Range Extent20,000-2,500,000 square km (about 8000-1,000,000 square miles)
Rank ReasonsEndemic to central Utah in woodland, sagebrush or meadow communities at 2135-3200 meters. Albee et al. (1988) list only 24 sites.
Range Extent CommentsCirsium clavatum is endemic to the Central Rocky Mountains in Colorado, Utah, and Wyoming (FNA 2006a). There are three varieties, of which Cirsium clavatum var. osterhoutii is the most range restricted as an endemic of the central mountains of Colorado.
Occurrences Comments24 sites in central Utah (Albee et al. 1988).
Threat Impact CommentsNative cirsium are increasingly at serious risk from a Eurasian flowerhead weevil (Rhinocyllus conicus Froeh.), which was first introduced in 1968 for biocontrol of Eurasian Carduus thistles such as the weedy alien Carduus nutans (musk thistle). The weevil is extending its range to new host species, as well as geographically; it already was released in southern Canada (British Columbia to Quebec) and the western and eastern U.S. (in many states, such as from Washington, California, Arizona and Texas to Idaho, Minnesota, New Jersey, Virginia and Tennessee). Some (but not all) native Cirsium species in Colorado, Nebraska and South Dakota - including populations in protected areas - have been shown to be damaged, with quantified decrease in seed production being "severe", over 70-85% loss. Furthermore, Cirsium species are fugitives which generally depend upon current seed production for their establishment and persistence (Louda et al. 1997; Strong 1997; pers. com. [overview talk 99-09-08 at TNC to Plant Conservation Alliance] by Carol Spurrier, BLM Colorado State Office).