A Thorny Subject

Most things with prickly exteriors have a soft side hidden in their interiors. Some sort of stenocereus (Latin for narrow candle) cactus, a group of very large, tree-like cacti that grow throughout many of the warmer areas of North, Central, and South America.  Because their growing tips are very sensitive to the cold, many of these columnar cacti spend the winter in Phoenix wearing Styrofoam cups on the ends of their branches.