Phoenix Close-Up

You’ve seen it every time you see a postcard of the desert: the giant Saguaro. Never mind that the Saguaro grows only in a small, defined area of the United States–the lower Sonoran Desert, which is in Arizona, a tiny bit of California, and Baja California and Mexico. Nope, if you see a cartoon about the hapless guy

Joshua Tree in the Mojave Desert.

crawling across the desert, there’s a Saguaro letting you know it’s a desert. If he were in the Mojave, the hapless guy would have to have a Joshua Tree letting you know where it is. A Joshua Tree looks like a cross between a bunch of straws and a muppet.

You also probably know that the Saguaro sucks up water when it rains, expanding it’s accordion-like ribs to hold water. While the Saguaro holds about 40 gallons of water after a rainfall, you

Saguaro cactus. This one is well-watered.

cannot stick a straw into it and get a drink of water when you become the hapless guy crawling across the desert. (Incidenally, the cactus is not pronounced Sag-u-AH-Roh, it’s pronounced Suh-WAR-oh.)

Why not? Because a Saguaro isn’t hollow. Nope, it’s packed full of fibers and long stick-like structures, called the skeleton. When a Saguaro dies, the skeleton is harvested for wood–I have a walking stick made from one of the ribs. The Saguaro is endangered and protected, so you can’t go cutting one down for the ribs. Or the water, for that matter.

Here is a cross section of the brother of the above Saguaro. Same yard, right next to it, but it died. OK, so maybe the fact that it got struck by lightning might have had something to do with it.

Cross-section of a saguaro

The cross section shows the outside edge, the dark-brown ribs surrounding the tough-spongy middle (which feels a lot like a dry loofa sponge). You can’t poke a straw into it. When the saguaro dies, the skin and vascular tissue beneath it disintegrate, and the inside tough-spongy layer crumbles, leaving the tall spikes standing.

Quinn McDonald is a naturalist and nature journaler who lives in The Valley. She had to take a ladder on her morning walk to get a good shot of the lightning-struck saguaro. Yes, she felt really dumb hauling a ladder on her morning walk.