| Cacti Guide: Images of many cactus genera as planted specimens in collections or in natural habitat, with horticultural advice and a discussion forum. |
| Cactus Museum: Photos and notes for many species from a cactus grower in Tucson, Arizona. |
| Coryphantha: Classification information, photo galleries, bibliography, distribution maps, and link directory. [German, English] |
| Keir's Botanical Photo Archive - Cactaceae: Images from the US. |
| Mark Faint's Cactus Page: Detailed information on Neolloydia, Notocactus, and Turbinicarpus. |
| Outdoor Cacti Photos: Photos of Opuntia, Echinocereus, and others, resources, and tips for growing and photographing them. |
| Peterocactus National Plant Collection: List of the nine species, endemic to southwestern Argentina, with images and brief descriptions of four. |
| Plants of the Cactaceae Family: Large image gallery of cacti cultivated in Phoenix, Arizona. |
| Rhipsalis, Lepismium, Hatiora, Schlumbergera: Information on plants in these four genera, including species lists with photos, cultivation and propagation details, and links to vendors and collections. |
| Southwestern Cacti: Information and photos for species native to the southwestern United States. |
| The Cactaceae: Description of the cactus family, with photos and short profiles of several representative species. |
Classical
