Jumping Cacti Can't Jump

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When I first heard of the dreaded "jumping cactus" I was more than a little curious. I had just moved to the West and had no experience with cacti in the wild. My relationship with this group of spiny plants had, up until that point, been limited to some unfortunate encounters trying to grow them on a windowsill at home. I had gotten quite used to using duct tape to remove their spines from my hands. Needless to say, the thought of a cactus "jumping" was a bit intriguing if not a little nerve-racking. 

The cactus in question here is commonly referred to as the jumping cholla. Scientifically speaking it seems less scary calling it Cylindropuntia fulgida. At the time of my first introduction I was much more botanically naive. Having witnessed first hand fluid movements of a sensitive plant (Mimosa pudica), or the lightening fast snap of a Venus fly trap (Dionea muscipula), a jumping cactus didn't seem too outlandish of an idea. 

In reality, jumping cholla do not jump. The common names comes from the fact that the individual stem segments of the plant are only weakly attached. The slightest touch will detach them. This gives unfortunate hikers the idea that the plant has physically jumped out and attacked. Needless to say, cholla are a spiny lot and each spine is covered in backward pointing barbs, which make removing them a painful experience. As a result, they not only fall off the plant readily, they grab on for a ride. 

A ride is exactly what they are looking for. Whereas plants like burdock (Arctium sp.) or tick trefoils (Desmodium sp.) have barbed seed capsules to facilitate seed dispersal, jumping cholla utilize this strategy as a form of vegetative reproduction. Stem segments that stick to the hair or into the skin of passing mammals can be carried quite a distance before they are successfully dislodged. If the cholla is lucky, this will happen in spot that is favorable for growth and thus a new plant can begin. 

The result of this is a rather quick lifestyle for this cactus. Stands of cholla can be relatively short lived. There is a lot of competition for light and space in mature cholla stands and being able to get as far away from that congestion is very beneficial in the long run. This mobile form of vegetative reproduction has worked quite well for the jumping cholla, much to the displeasure of anyone that has come into contact with this plant. As such, an entire mythos has developed around Cylindropuntia fulgida

Photo Credit: meligrosa (https://www.flickr.com/photos/meligrosa/8396656703/)

Further Reading:

http://www.jstor.org/stable/10.1086/425665?seq=1#page_scan_tab_contents