He has studied cactuses for decades; his college thesis was on the prickly pear. Mark Dimmitt, director of natural history at the Arizona-Sonora Desert Museum near Tucson, told the Arizona Daily Star that staff members have noticed more freeze damage on saguaros on lower ground.
The crested, or cristate, saguaro is an example of a persisting oddity. These cactuses have fan-like growths. The cells divide horizontally instead. No one knows exactly why the crested variation happens, but some experts suspect damage from frost or lightning, a genetic abnormality or hormonal quirk. All rights reserved. Creative Commons. Related story. Share this story:. As the saguaro continues to grow, its much older nurse tree may die.
Some scientists believe that competition from the saguaro may lead to the death of the nurse tree by taking water and nutrients from the soil in the immediate area. Though normally found at the terminal end of the main trunk and arms, flowers may also occur down the sides of the plant. Flowers will continue to be produced throughout a saguaro's lifetime.
An adult saguaro is generally considered to be about years of age. It may weigh 6 tons or more and be as tall as 50 feet. The average life span of a saguaro is probably - years of age.
However, biologists believe that some plants may live over years. These cacti have fan-like growths. The cells divide horizontally instead. These cacti are descendents of the first genetically sequenced saguaro cactus.
They're about two years old. This cactus fell and smashed to pieces after a storm. The cross-section shows how strong woody fibers, sometimes ribs, give the saguaro structure. A saguaro cactus near the Superstition Mountains. A saguaro cactus blooms in Tempe. One theory is that frost causes the sauguaro cacti's arms to droop down.
Martin Wojciechowski is an ASU evolutionary biologist who focuses on plants.
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