| Rating | Plant Name | Thumbnail |
| 1 | Alameda County Thistle
Cirsium quercetorum | No Images Yet |
| 2 | Ashland Thistle
Cirsium ciliolatum | No Images Yet |
| 3 | Barneby's Thistle
Cirsium barnebyi | No Images Yet |
4  | Bull Thistle, Spear Thistle
Cirsium vulgare |  |
5  | Bull Thistle, Yellow Thistle, Purple Thistle, Spiny Thistle
Cirsium horridulum |  |
| 6 | Cainville Thistle
Cirsium calcareum | No Images Yet |
| 7 | Canada Thistle, Creeping Thistle
Cirsium arvense |  |
| 8 | Carolina Thistle, Purple Thistle, Soft Thistle
Cirsium carolinianum |  |
| 9 | Cirsium
Cirsium subcoriaceum | No Images Yet |
| 10 | Cirsium
Cirsium nipponicum |  |
| 11 | Cliff Thistle
Cirsium turneri | No Images Yet |
| 12 | Clustered Thistle
Cirsium brevistylum | No Images Yet |
13  | Cobweb Thistle, Cobwebby Thistle, Red Thistle, Venus Thistle
Cirsium occidentale | No Images Yet |
| 14 | Douglas Thistle
Cirsium douglasii | No Images Yet |
| 15 | Dwarf Thistle
Cirsium drummondii | No Images Yet |
| 16 | Edible Thistle
Cirsium edule |  |
| 17 | Engelmann's Thistle
Cirsium engelmannii | No Images Yet |
| 18 | Field Thistle
Cirsium discolor |  |
| 19 | Fish Lake Thistle
Cirsium clavatum | No Images Yet |
| 20 | Hall's Thistle
Cirsium hallii | No Images Yet |
| 21 | Hill's Thistle, Prairie Thistle
Cirsium hillii | No Images Yet |
| 22 | Hooker's Thistle
Cirsium hookerianum |  |
| 23 | Iowa Thistle
Cirsium iowense | No Images Yet |
| 24 | Ivory Thistle
Cirsium diacanthus |  |
| 25 | Jeweled Thistle
Cirsium araneans | No Images Yet |
| 26 | LeConte's Thistle
Cirsium lecontei |  |
| 27 | Longstyle Thistle
Cirsium longistylum | No Images Yet |
| 28 | Marsh Thistle
Cirsium palustre |  |
| 29 | Melancholy Thistle, Curly Head
Cirsium heterophyllum |  |
| 30 | Mt. Tamalpais Thistle
Cirsium amblylepis | No Images Yet |
| 31 | Navajo Thistle
Cirsium navajoense | No Images Yet |
| 32 | New Mexico Thistle
Cirsium neomexicanum |  |
| 33 | Nutall's Thistle
Cirsium nuttallii |  |
| 34 | Ornamental Thistle 'Atropurpureum'
Cirsium rivulare |  |
| 35 | Palouse Thistle
Cirsium brevifolium | No Images Yet |
| 36 | Pasture Thistle
Cirsium pumilum | No Images Yet |
| 37 | Peregrine Thistle
Cirsium cymosum | No Images Yet |
| 38 | Pitcher's Thistle, Sand Dune Thistle
Cirsium pitcheri |  |
| 39 | Prairie Thistle
Cirsium canescens | No Images Yet |
| 40 | Queen Thistle
Cirsium chellyense | No Images Yet |
