Cirsium eatonii

Cirsium eatonii, commonly known as Eaton's thistle or mountaintop thistle, is a North American species of flowering plants in the family Asteraceae.^[2][3]

Cirsium eatonii
Cirsium eatonii var. clokeyi in Southern Nevada
Conservation status
Secure  (NatureServe)
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Clade:	Angiosperms
Clade:	Eudicots
Clade:	Asterids
Order:	Asterales
Family:	Asteraceae
Genus:	Cirsium
Species:	C. eatonii
Binomial name
Cirsium eatonii (A.Gray) B.L.Rob.
Synonyms[1]
Synonymy Carduus leiocarpus A.Heller Carduus leiocephalus (D.C.Eaton) A.Heller Cirsium eatonii var. harrisonii S.L.Welsh Cirsium eriocephalum var. leiocephalum D.C.Eaton Cnicus eatonii A.Gray Carduus hookerianus var. eriocephalus (A.Gray) A.Nelson, syn of var. eriocephalum Carduus scopulorum Greene, syn of var. eriocephalum Cirsium eriocephalum A.Gray 1864 not Wallr. 1840, syn of var. eriocephalum Cirsium hookerianum var. eriocephalum (A.Gray) A.Nelson, syn of var. eriocephalum Cirsium scopulorum (Greene) Cockerell, syn of var. eriocephalum Cirsium scopulorum (Greene) Cockerell ex Daniels, syn of var. eriocephalum Cnicus eriocephalus A.Gray, syn of var. eriocephalum Carduus hesperius A.Heller, syn of var. hesperium Carduus hookerianus var. hesperius (Eastw.) A.Nelson, syn of var. hesperium Cirsium hesperium (Eastw.) Petr., syn of var. hesperium Cnicus hesperius Eastw., syn of var. hesperium Carduus polyphyllus Rydb., syn of var. murdockii Carduus tweedyi Rydb., syn of var. murdockii Cirsium murdockii (S.L.Welsh) Cronquist, syn of var. murdockii Cirsium polyphyllum (Rydb.) Petr., syn of var. murdockii Cirsium tweedyi (Rydb.) Petr., syn of var. murdockii Cirsium peckii L.F.Hend., syn of var. peckii

The species has been found in Idaho, Montana, New Mexico, Wyoming, Nevada, Utah and Colorado.^[4]

Description

Cirsium eatonii is highly variable. It is an erect herb up to 150 cm (60 inches or 5 feet) tall in some populations. The entire foliage is more or less spiny. One plant produces several flower heads with pink to purple or yellow flowers. The species grows at high elevations in grasslands, sagebrush steppes, open savannahs, etc.^[3]

Varieties^[1][3]

A number of varieties have been identified, which include:

• Cirsium eatonii var. clokeyi - Clokey thistle, Spring Mountains thistle, white-spine thistle. This variety is rare and uncommon. - Nevada^[5]
• Cirsium eatonii var. eatonii - Nevada, Utah
• Cirsium eatonii var. eriocephalum - alpine thistle, mountain thistle - Colorado, New Mexico, Utah
• Cirsium eatonii var. hesperium - tall mountain thistle - Colorado
• Cirsium eatonii var. murdockii - northern mountain thistle - Colorado, Idaho, Montana, Nevada, Utah, Wyoming
• Cirsium eatonii var. peckii - ghost thistle, Steens Mountain thistle - Nevada, Oregon
• Cirsium eatonii var. viperinum - Snake Range thistle - Nevada

Var. eriocephalum in northern New Mexico.