I grew up in the Sonoran Desert of Arizona, spending 25 years of my life there. As an inveterate desert rat and enthusiastic natural historian I soon got to know some of the more prickly inhabitants thereof - the cacti! My first remembered experience was of falling on a cholla at Boot Hill Graveyard (the touristy site) at Tombstone, but I got to understand that cacti should be admired from a distance. The flowers of most are well worth the examination and some are, as they say in the song, "lovelier than orchids" (although as also an admirer of the non-spiny orchids I might take some exception to that!) Still, they can be exceptionally beautiful and their associations with other biota are fascinating. A visit to the giant cactus forest of the Sonoran Desert is almost a visit to a totally alien planet, even to those who grew up there.
Cacti are (with the exception of one genus of epiphytic species) totally New World in distribution. The epiphytic species found on the Atlantic Coast of Africa was almost certainly introduced, perhaps at a fairly early time. Because of the more recent introduction of New World species many areas of the globe now have cacti, especially Prickly Pears, including North Africa and Australia. In the latter case a successful biological control program about wiped the problem out.
Of the many places that I have seen these spiny plants (often confused with other spiny flora, such as agaves, yuccas, euphorbias, and others) probably the most memorable (outside of the Arizona cactus forest) were the Baja California Desert, the dry forest along Puerto Rico's Caribbean coast and the middle of the Florida Keys. In Baja's strange desert, the cardon, organ pipe, devil and old-man cacti, join with the tree ocotillo, palo blanco, and numerous others to form an almost Lewis Carol inspired landscape. The huge cardon (even larger than the saguaro of Arizona) towered over the plains near Mulege like some sort of weird power poles. Along Puerto Rico's Caribbean coast the Turk's cap and barbed-wire cacti added yet another surrealistic effect to a dry "forest" of frangipani with fire ant covered rocks. In the Florida Keys several species of cacti reiterated the basic dryness of the islands, despite their tropic location.
Chollas are among the spiniest of the cacti, as I have learned on several ocasions to my sorrow. The "Teddy Bear" Cholla is anything but cuddly and the others are not any better. Still a few have attractive flowers and the strange attached fruits of the Chain Cholla are pretty strange. Chollas are often listed in Cylindropuntia and Prickly Pears in Platyopuntia.
Chain Cholla (Opuntia fulgida) southwest of the Superstition Mountains in Arizona.
Tree Cholla (Opuntia imbricata ) in bloom, New Mexico.
Staghorn Cholla (Opuntia versicolor) in bloom, Superstition Mountains, Arizona.
Continued over the fold.
Beavertail Cacti and their close relatives the Prickly Pears are sometimes placed in the genus "Platyopuntia." The flowers can be very attractive, but even the seemingly "spineless" Beavertails have tiny hair-like spines called glochids that can be excruciatingly painful once embedded in the skin. The large spines of the Prickly Pear are even worse, as far as real damage goes. These cacti, and the Chollas, are best admired from a safe distance. Even a slight touch can embed a nasty spine or multiple glochids into unprotected skin.
Beavertail Cactus (Opuntia basilaris) Maricopa County, Arizona.
The various "Cereus" cacti, unlike the Opuntia series, tend to be columnar, but some, like the saguaros and cardon, can have branches. A few are creeping or climbing. They include the largest cacti known, the Cardon and the Saguaro. Southern Arizona is the northernmost part of the ranges of both Senita and Organ Pipe Cacti. These cacti are night-flowering and often pollenated by bats. In addition an entire community of organisms are tied to the giant cacti. Hawks build nests on them, elf owls and woodpeckers live in burrows inside the cacti and many organisms are involved with them in one way or another, even after they die. I have used "Cereus" as the generic name for this whole series, but these days other generic names are used, such as Carnegiea for the Saguaro, Pachycereus for the Senita and Stenocereus for the Organ Pipe Cactus.
Old Man Cactus or Senita (Cereus schottii) in mountains south of Sonoyta, Sonora.
Organ Pipe Cactus (Cereus thurberi) on the Plains of Sonora north of Hermosillo, Sonora. Tree Ocotillo in background.
Saguaro (Cereus giganteus) and Teddy Bear Cholla (Opuntia bigelovii), Superstition Mountains, Arizona.
Close up of Saguaro, Superstition Mountains of Arizona.
Cactus forest south of Superstition Mountains (in distance), Pinal County, Arizona.
There are many species of smaller cacti, including the very neat fishhook types. I well remember coming upon a colony of pink-flowering Neomammlliaria microcarpa in a desert pavement area on a small ridge in the Yuma desert when I was a kid. These were the kind of discoveries that made being a desert rat naturalist worthwhile! Other quite spiny, but very beautiful, smaller cacti include the many species of hedgehogs. These include species with pink, green or bright red flowers.
Hedgehog Cactus (Echinocereus fasciculatus) in bloom, south of Superstition Mountains, Arizona.
Red Hedgehog Cactus (Echinocereus coccineus) in a New Mexico garden.
The species of barrel-like cacti are perhaps a bit larger - I have found some individuals in the California Desert (Anza-Borrego State Park) that were as tall as a human. The weird Turk's Cap cacti of the Caribbean islands were quite prevalent on the south coast of Puerto Rico and the common Barrel Cacti of the Chihuahuan and Sonoran Deserts are characteristic of the bajadas (slopes) of desert mountain ranges.
Turk's Cap Cactus (Melocactus intortus) on the Caribbean Coast of Puerto Rico.
Barrel Cactus (Ferocactus wislizenii), Organ Mountains of New Mexico.
Barrel Cactus (Ferocactus wislizenii) in bloom, Organ Mountains of New Mexico.
Note: PLEASE LEAVE WILD CACTI IN THE WILD! If you are interested in raising cacti buy nursery-raised specimens.
Reference:
Benson, Lyman. 1982. The cacti of the United States and Canada. Standford University Press. This is, in my opinion, the book for the cacti in North America, north of Mexico. Very well written and wonderfully illustrated. Some names have changed.
As usual, all photographs are by me.