Sunday, September 27

Joshua Tree

Yucca Brevifolia
We spend the day in Joshua Tree National Park, about an hour's drive from Palm Springs.

Only found here in the Mojave Desert is the Joshua tree, the largest of the yuccas. Its height varies from 15-40 feet with a diameter of 1-3 feet. They grow 2 to 3 inches a year, takes 50 to 60 years to mature and they can live 150 years.

Joshua trees (and most other yuccas) rely on the female pronuba moth for pollination. No other animal visiting the blooms transfers the pollen from one flower to another. In fact - the female yucca moth has evolved special organs to collect and distribute the pollen onto the surface of the flower. She lays her eggs in the flowers' ovaries, and when the larvae hatch, they feed on the yucca seeds.

Without the moth's pollination, the Joshua tree could not reproduce, nor could the moth, whose larvae would have no seeds to eat. Although old Joshua trees can sprout new plants from their roots, only the seeds produced in pollinated flowers can scatter far enough to establish a new stand.

Mormon pioneers are said to have named this species "Joshua" tree because it mimicked the Old Testament prophet Joshua waving them, with upraised arms, on toward the promised land. This unique species grows abundantly at Joshua tree.
(Source: park info guide)