Making real science accessible and interesting for all people.
Friday, November 2, 2012
Barrel Cactus Part 1
Compass Barrel cactus
The barrel cactus is one of the most common cacti in the Southwest. There are four different species common to this area of the country, the most common of which are the compass barrel and the California barrel. It can be extremely difficult to distinguish between these two common species of barrels. In southern Arizona, such as around Tucson, the compass barrel is the most common of the two cacti. In central Arizona such as around Phoenix, southern California, and even into the depths of the Grand Canyon the California barrel cactus is the most common. Their ranges overlap in central Arizona and their similarities are pretty extensive. Without closer investigation you may not be able to determine what specific species a particular barrel is, there are however a few differences that may help in identification. First off is shape. Of course, barrel cacti are all sort of barrel shaped. The compass barrel is a little more wide and plump than the California barrel. The California barrel is a little skinnier. The second way to distinguish between the two is by looking at the spines. Both have very interesting spines which are often red colored. This red coloration gives a sharp contrast to the dark green of the cacti's body, especially after a rare rainfall. Both cacti also have flattened central spines that have a ribbing pattern on them. The central spines are also hooked, giving both cacti another common name of fishhook barrels. Compass barrel cacti spines are however considerably more hooked than California barrels. Compass barrel central spines are a full "fishhook" shape and were in-fact used as fishhooks by some Native Americans. California barrel central spines are closer to a 90 degree curve than an actual fishhook. These are the best ways, though not necessarily foolproof ways of distinguishing the two while out in the desert.
In our next post we will talk about the leaning habit of barrel cacti.