| Rating | Plant Name | Thumbnail |
| 1 | Tall Thistle
Cirsium altissimum |  |
| 2 | Mt. Tamalpais Thistle
Cirsium amblylepis | No Images Yet |
| 3 | Rose Thistle
Cirsium andersonii | No Images Yet |
| 4 | Jeweled Thistle
Cirsium araneans | No Images Yet |
5  | Canada Thistle, Creeping Thistle
Cirsium arvense |  |
| 6 | Barneby's Thistle
Cirsium barnebyi | No Images Yet |
| 7 | Palouse Thistle
Cirsium brevifolium | No Images Yet |
| 8 | Clustered Thistle
Cirsium brevistylum | No Images Yet |
| 9 | Cainville Thistle
Cirsium calcareum | No Images Yet |
| 10 | Prairie Thistle
Cirsium canescens | No Images Yet |
11  | Carolina Thistle, Purple Thistle, Soft Thistle
Cirsium carolinianum |  |
| 12 | Queen Thistle
Cirsium chellyense | No Images Yet |
| 13 | Ashland Thistle
Cirsium ciliolatum | No Images Yet |
| 14 | Fish Lake Thistle
Cirsium clavatum | No Images Yet |
| 15 | Whitespine Thistle
Cirsium clokeyi | No Images Yet |
| 16 | Rosette Thistle
Cirsium congdonii | No Images Yet |
| 17 | Slough Thistle
Cirsium crassicaule | No Images Yet |
| 18 | Peregrine Thistle
Cirsium cymosum | No Images Yet |
19  | Ivory Thistle
Cirsium diacanthus |  |
| 20 | Field Thistle
Cirsium discolor |  |
| 21 | Douglas Thistle
Cirsium douglasii | No Images Yet |
| 22 | Dwarf Thistle
Cirsium drummondii | No Images Yet |
| 23 | Edible Thistle
Cirsium edule |  |
| 24 | Engelmann's Thistle
Cirsium engelmannii | No Images Yet |
| 25 | Woolly Thistle
Cirsium eriophorum | No Images Yet |
| 26 | Hall's Thistle
Cirsium hallii | No Images Yet |
| 27 | Melancholy Thistle, Curly Head
Cirsium heterophyllum |  |
| 28 | Hill's Thistle, Prairie Thistle
Cirsium hillii | No Images Yet |
| 29 | Hooker's Thistle
Cirsium hookerianum |  |
| 30 | Bull Thistle, Yellow Thistle, Purple Thistle, Spiny Thistle
Cirsium horridulum |  |
| 31 | Iowa Thistle
Cirsium iowense | No Images Yet |
| 32 | Sea Thistle, Japanese Thistle, Plumed Thistle
Cirsium japonicum |  |
| 33 | Sea Thistle, Japanese Thistle, Plumed Thistle 'Pink Beauty'
Cirsium japonicum | No Images Yet |
| 34 | LeConte's Thistle
Cirsium lecontei |  |
| 35 | Longstyle Thistle
Cirsium longistylum | No Images Yet |
| 36 | Swamp Thistle
Cirsium muticum |  |
| 37 | Swamp Thistle
Cirsium muticus | No Images Yet |
| 38 | Navajo Thistle
Cirsium navajoense | No Images Yet |
| 39 | New Mexico Thistle
Cirsium neomexicanum |  |
| 40 | Cirsium
Cirsium nipponicum |  |
