A cactus (plural cacti, cactuses, or less commonly, cactus) is a member of the plant family Cactaceae, a family comprising about 127 genera with some 1750 known species of the order Caryophyllales. The word "cactus" derives, through Latin, from the Ancient Greek κάκτος, kaktos, a name originally used by Theophrastus for a spiny plant whose identity is now not certain. Cacti occur in a wide range of shapes and sizes. Most cacti live in habitats subject to at least some drought. Many live in extremely dry environments, even being found in the Atacama Desert, one of the driest places on earth. Cacti show many adaptations to conserve water. Almost all cacti are succulents, meaning they have thickened, fleshy parts adapted to store water. Unlike many other succulents, the stem is the only part of most cacti where this vital process takes place. Most species of cacti have lost true leaves, retaining only spines, which are highly modified leaves. As well as defending against herbivores, spines help prevent water loss by reducing air flow close to the cactus and providing some shade. In the absence of leaves, enlarged stems carry out photosynthesis. Cacti are native to the Americas, ranging from Patagonia in the south to parts of western Canada in the north—except for Rhipsalis baccifera, which also grows in Africa and Sri Lanka. Learn more about Cactus
View all family groups for: Plant
Cactus Species Videos
View All Cactus Videos
Common Name | Scientific Name | Conservation Status |
Barrel Cactus ( videos) | Copiapoa longistaminea | Not Available |
Beavertail Pricklypear (6 videos) | Opuntia basilaris | Not Available |
Buckthorn Cholla ( videos) | Cylindropuntia acanthocarpa | Not Available |
Candy Barrel Cactu ( videos) | Ferocactus wislizeni | Not Available |
Coastal Pricklypear (1 videos) | Opuntia littoralis | Not Available |
Dragon Fruit Cactus ( videos) | Hylocereus undatus | Not Available |
Engelmann's Hedgehog Cactu (15 videos) | Echinocereus engelmannii | Not Available |
Freeway Iceplant (8 videos) | Carpobrotus edulis | Not Available |
Graham's Nipple Cactu (2 videos) | Mammillaria grahamii | Not Available |
Indian-fig ( videos) | Opuntia ficus-indica | Not Available |
Jumping Cholla ( videos) | Cylindropuntia fulgida | Not Available |
Kingcup Cactu ( videos) | Echinocereus triglochidiatus | Not Available |
Lava Cactus ( videos) | Brachycereus nesioticus | Not Available |
Ocotillo (147 videos) | Fouquieria splendens | Not Available |
Organ Pipe Cactus (10 videos) | Stenocereus thurberi | Not Available |
Purple Queen (0 videos) | Tradescantia pallida | Not Available |
Queen (22 videos) | Danaus gilippus | Not Available |
Saguaro (184 videos) | Carnegiea gigantea | Not Available |
Spiny Cholla ( videos) | Cylindropuntia spinosior | Not Available |
Spinystar (2 videos) | Escobaria vivipara | Not Available |
Teddy Bear Cholla ( videos) | Cylindropuntia bigelovii | Not Available |
Texas Prickly Pear ( videos) | Opuntia engelmannii | Not Available |