Below is a list of all cacti found in Colorado; the main species first, those with a photograph and full description page, followed by all other species, generally less common. Most of the limited number of species are small and low-growing.
Escobaria missouriensis, Missouri foxtail cactus (AZ, CO, ID, KS, MT, ND, NE, NM, OK, SD, TX, WY)
Opuntia cymochila, grassland prickly pear (CO, KS, NE, NM, OK, TX)
Opuntia macrorhiza, Twist spine prickly pear (AZ, CO, ID, KS, MT, NE, NM, OK, SD, TX, UT, WY)
Sclerocactus glaucus, Colorado hookless cactus (CO)
Sclerocactus mesae-verdae, Mesa Verde fishhook cactus (CO, NM)