There are several different types of saguaro mutation that do not lead to the formation of the classic fan-shaped crest on the tip of the plant. The study of these related forms may give important insight into the underlying genetic cause of saguaro cristation. They're also just fun to look at!

I suspect that the same defective gene that causes the formation of fan-shaped crests (in combination with physical damage to the growing tip) also causes irregular patterns in the pleats of some saguaros.

Saguaros with wavery patterns like these are known as "spiral" or "checkerboard" saguaros:

Normally, a saguaro arm joins the main trunk at a ring-shaped joint. Rarely, an arm or trunk will split smoothly without the ring, forming a "Y" shape. I suspect this is also evidence of the defective gene; sometimes a "Y" is also accompanied by irregular pleating.

These are also called "globular" saguaros. This mutation causes the arms of the saguaro to grow in rounded, tumerous masses.

2/20/2009 Going...

5/27/2011 going...

4/5/2012 going...

11/19/2012 GONE!

11/19/2012 On ground.

These are also called "segmented" or "watermelon" saguaros because the arms form in clusters of short segments (joints) which can resemble a pile of melons.

This mutation in the barrel cactus appears similar to the glomerate saguaros.

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