Unidentified Thistle: Cirsium sp. - Can you help identify this thistle?
Anderson's Thistle: Cirsium andersonii -
Canada Thistle, Creeping Thistle: Cirsium arvense (Synonyms: Cirsium arvense var. arvense, Cirsium arvense var. horridum, Cirsium arvense var. mite) -
Palouse Thistle: Cirsium brevifolium (Synonym: Cirsium palousense) -
Short-styled Thistle, Cluster Thistle, Clustered Thistle: Cirsium brevistylum -
Gray-green Thistle: Cirsium cymosum var. canovirens (Synonym: Cirsium canovirens) -
Peregrine Thistle, Greene's Thistle: Cirsium cymosum var. cymosum -
Brewer's Thistle, Swamp Thistle: Cirsium douglasii var. brewerii (Synonyms: Cirsium breweri, Cirsium douglasii var. canescens) -
Steens Mountain Thistle, Peck's Thistle: Cirsium eatonii var. peckii (Synonym: Cirsium peckii) - Thistle with a single erect stem having flower heads clustered at the base of each leaf along of the stem. 2 to 4 feet tall.
Macoun's Thistle: Cirsium edule var. macounii (Synonyms: Carduus macounii, Cirsium macounii) -
Indian Thistle, Edible Thistle: Cirsium edule var. wenatchense -
Elk Thistle, Leafy Thistle: Cirsium foliosum (Synonym: Carduus foliosus) -
White Thistle, Hooker's Thistle: Cirsium hookerianum -
Intermountain Thistle, Jackson Hole Thistle: Cirsium inamoenum var. inamoenum (Synonyms: Synonyms: Cirsium subniveum, Cirsium utahense) -
Snowy Thistle, Snowwool Thistle: Cirsium occidentale var. candidissimum (Synonym: Cirsium pastoris) -
Yellowspine Thistle: Cirsium ochrocentrum var. ochrocentrum
Mountain Thistle, Fringe-bract Thistle: Cirsium remotifolium var. odontolepis (Synonyms: Cirsium callilepis, Cirsium callilepis var. callilepis, Cirsium callilepis var. oregonense, Cirsium callilepis var. pseudocarlinoides, Cirsium centaureae, Cirsium remotifolium ssp. oregonense, Cirsium remotifolium ssp. pseudocarlinoides) -
Dinnerplate Thistle, Elk Thistle, Meadow Thistle, Sessile Thistle, Shasta Valley Thistle, Stemless Thistle, Toiyabe Thistle: Cirsium scariosum (Synonyms: Carduus americanus, Carduus coloradensis, Cirsium acaule var. americanum, Cirsium acaulescens, Cirsium americanum, Cirsium butleri, Cirsium coloradense, Cirsium coloradense ssp. acaulescens, Cirsium coloradense ssp. longissimum, Cirsium congdonii, Cirsium drummondii ssp. lanatum, Cirsium drummondii ssp. lanatum, Cirsium drummondii ssp. latisquamum, Cirsium drummondii ssp. vexans, Cirsium drummondii var. acaulescens, Cirsium drummondii var. oregonense, Cirsium erosum, Cirsium hookerianum var. scariosum, Cirsium kelsey, Cirsium lacerum, Cirsium magnificum, Cirsium minganense, Cirsium oreophilum, Cirsium quercetorum, Cirsium scariosum var. americanum, Cirsium scariosum var. robustum, Cirsium scariosum var. scariosum, Cirsium scariosum var. thorneae, Cirsium scariosum var. toiyabense, Cirsium tioganum, Cirsium tioganum var. coloradense, Cirsium tioganum var. tioganum, Cnicus drummondii var. acaulescens, Cnicus tioganus) - A fairly easy thistle to identify in that it is frequently without stems. Stems generally very short and thick, with the flower heads sessile. Corollas white to a pale pink-purple. Leaves spiny, but entire to somewhat scalloped.
Wavy-leaf Thistle: Cirsium undulatum (Synonym: Cirsium undulatum var. undulatum) -
Bull Thistle, Common Thistle: Cirsium vulgare (Synonyms: Carduus vulgarae, Cirsium lanceolatum) -