Even a non-artist like me can make you think of the desert with just a few squiggles of a felt-tip marker. See above? I did it already…and what does the trick is that everyone has seen the image forever, even though the cactus in the picture—the saguaro—grows only in one place on earth, the Sonora desert, in the southwestern U.S. and northwestern Mexico.
We just spent a Christmas week visiting friends who live south of Tucson, AZ. An early morning walk with my friend introduced me to a number of the different cacti growing there in what I’ve started to think of as the Spine Garden. Some are gorgeous, some not so much, and one or two are even tricky. Some chollas (pronounced ‘choya') drop spine-laden bits that can blow onto you or pierce the skin if stepped on. This one is called a "Jumping Cholla" because its spiny bits seem to jump out at you in a slight breeze.
There are, of course, many more cacti than I saw, and I saw them in only one season. There are more than 1500 different kinds, each with its own characteristics and often only a very small growing area. They are native to many areas of the Americas, and to a band across central Africa…but few species grow in more than one area.
Despite their obvious differences, cacti have a number of things in common. They don’t have leaves, so their photosynthesis takes place in their stems. The stems are usually ribbed or have some other way to expand to hold water internally for dry spells (they can expand quite a bit!). Smaller ones tend to be round, like the barrel cactus below; bigger ones are more likely to take on column shapes like the saguaros above. Pronounced ‘sawaro,’ by the way! Most saguaro are just a straight column until about age 75; only then do they begin to grow arms. A really big one can weigh 5 tons (a popular souvenir postcard shows the back of a Cadillac crushed under a fallen 20-footer).
The spines of this “golden barrel” cactus serve several purposes. They protect the plant against being eaten, and they help prevent water loss by slowing down air flow around the plant. They also help the plants reproduce…spiked seeds don’t blow too far away!
Another whole group of cacti have flat paddles—these are the prickly pears, which come in a wide variety of colors, as you can see in the pictures above. Prickly pears and their cousins the bristly pear are also called “paddle cactus,” or “nopales.” They actually produce an edible fruit…but only after it’s very carefully peeled, because the smaller hair-like spines can cause serious damage if eaten. Like almost all cacti, they are really native only to the Americas, but have been spread by humans to Africa and Australia. Below, a bristly pear, with a velvet-like surface and only small spines.
The actual cacti are not the only residents of the Spine Garden; there are also agaves of various kinds; they are also succulents but belong to a different group. Here’s a desert view with a prickly, saguaro, golden barrels, and on the right, an agave.
And there are true trees in the Arizona desert. The area south of Tucson, along the Santa Cruz river, is a major pecan growing area, but two of the most common desert trees are the cottonwood, visible behind this “fishhook” barrel cactus (you guessed it…the spines can hook you and stay), and the ocotillo (right) which looks more like a bush. This one is braving out the winter: Not all of its small green leaves are gone.
And last, but not least: What’s inside a cactus? I grew up with the cartoon version—someone punctures the saguaro, water runs out, and it sags over like a deflated balloon. Doesn’t happen; the inside of the saguaro is a system of woody tubes that keep it upright (often up to 20 feet or more) and store water. Here’s a view of a saguaro skeleton, with a close-up as well.
So, if I started my trip with an idea of the desert as empty except for a lonesome cactus, I came home with a far more varied and colorful picture in my head, and even a picture of a desert Christmas whimsy:
The slideshow below contains additional images...enjoy!