It's estimated that 1 in 200,000 saguaro cacti grow a crest formation beginning at about 60 to 80 years old. These saguaros are called crested or cristate saguaro. Biologists don't know for certain why some saguaro cacti grow this way. Some speculate that "saguaros are genetically programmed with the ability to crest but require an external trigger to stimulate the gene." One such trigger is thought to be frost.
Places where you can see crested saguaros include:
- The Desert Botanical Gardens (The garden has two.)
- The Arizona-Sonora Desert Museum
- University of Arizona Campus (northeast of Old Main)
See The National Park Service Crested Saguarosopens a new window.
"Cristate Saguaros." Arizona Daily Star. June 9, 2004. Page E1
Find the information you need by calling the library's Infoline at 520-791-4010 or by sending your question to Askalibrarian.