Rains May Unlock An Enduring Mojave Mystery

A Joshua tree flower cluster | Photo:

“It’s make or break time. If we don’t get any rain in the desert between now and March, it’s not gonna happen. But if enough precipitation leaks over the mountains to give the Mojave Desert a few good showers or a blanket of snow, then we might just see one of the desert’s least-understood phenomena take place, as Joshua trees work to create a new generation of themselves.

Don’t get me wrong: we understand the basics quite well. In years where the Joshua trees have gotten enough winter water and a good freeze, some of the leaf buds at the ends of those ungainly branches will turn into flower buds. Between late February and April, those flower buds will open into big, tight clusters of cream-colored flowers.

At about the same time, legions of little dusky yucca moths will emerge from the ground and flit around the blossoms. The moths mate, and then the females get to work pollinating the Joshua tree’s flowers. It’s a remarkable process: the females have specially evolved tentacles near their mouths, unique in the insect world, with which they collect pollen and pack it into little balls. They then move from flower to flower, take a bit of pollen off the ball and wedge it into the floral ovary, thus fertilizing the flower.’ (Read article KCET)