Certainly one of the most painful hitchhiking plants in the southwestern United States is jumping cholla (Opuntia bigelovii). The spines are exceedingly difficult to pull out of rubber soles and elastic human skin. Like other kinds of cholla cactus, the cylindrical stem segments are densely covered with slender, barbed spines. In fact, this species is sometimes called "teddy-bear cholla" because of its dense covering of spines. What makes this cholla so unique is that the stem segments or joints break off with the slightest touch and become firmly attached to various body extremities. Unlike the unrelated but truly amazing Mexican jumping beans and California jumping galls, this cholla doesn't really jump. If you barely touch or brush against the spines and then suddenly jerk away, the fuzzy stem fragment will be instantaneously upon you. Trying to pull out the barbed spines is not only frustrating and excruciating, but usually results in the joint or fragment becoming attached to another part of your anatomy. On a field trip to the Anza-Borrego Desert of San Diego County, several students attempted to remove a segment from a lady's shoe, only to have it transferred to the shoes of each chivalrous male. It finally ended up on the hand of a screaming (bleeding) student who promptly flipped it full force into Mr. Wolffia's groin region. From that day forward the Wayne's Word staff always carries a pair of needle-nose pliers when walking through jumping cholla country.

Closeup microphotography with a scanning electron microscope (SEM) reveals why the spines of jumping cholla are so tenacious and difficult to pull out of skin. The spine is covered with sharp, overlapping scales or barbs that lie flat and allow the spine to penetrate skin readily like a very sharp needle. When you try to remove a spine, you are pulling against hundreds of tiny scales. In the process, other spines penetrate the skin from all directions, making the extraction very painful and seemingly hopeless.

The easily fragmented stem segments of jumping cholla are one of nature's most effective methods of hitchhiking and vegetative reproduction. Thickets of jumping cholla covering entire hillsides or alluvial fans may have developed from fragmented stem segments that became rooted in the desert soil. Although jumping cholla produces flowers, the seeds of most populations are typically sterile and reproduction is accomplished without sexual reproduction (technically referred to as apomixis). You could say that jumping cholla is a master in the art of hitchhiking and cloning itself.