Sometimes cacti or other plants display a quirky growth pattern called cresting or fasciation. Some possible causes include genetic mutation, lightening strike, freeze damage, insect attack and bacterial infection, but scientist don't agree on the reason. Cresting is rare in saguaros, and
usually begins at the top when the plant is several feet tall. Instead of growing in the typical way, the cactus fans out into undulating folds and ribbons.
Here are some of the crested saguaros (Cereus giganteus f. cristate) we've observed around Tucson, Arizona: