The oddly shaped Joshua Tree is usually mistaken for a cactus, but it actually belongs to the taxonomic family Agavaceae. It can be found found dominating some desert wilderness areas, where it inspired Mormon pioneers to name it after Joshua from the Old Testament, who ushered the Israelites from the wilderness into the Promised Land.
The height of a Joshua tree can range anywhere from 15ft. to 40ft, and has the diameter of 1-3 feet. The flowers that live on the Joshua tree are bell shaped and they range anywhere from 1.25 inches to 1.5 inches, and they have six creamy yellowish sepals. The trunk of the Joshua tree is mostly made up of fibers, it is hard to tell how old the Joshua Trees have been there, because unlike trees they don’t have the growth rings. Although a biologist determined that a Joshua tree in Joshua Tree National Park has lived over 900 years. The leaves of a Joshua Tree are spiny and are also faced upward to catch moisture in the air, then once it receives the moisture it moves the moisture in into the limbs and trunk.
Joshua Trees reproduce sexually with the assistance of a small white moth called the Yucca moth (Pronuba Tegeticula synthetica). The Yucca moth is the only species of insect to pollinate the Joshua tree, but the relationship between the two goes much deeper demonstrating a classic example of a symbiotic relationship known as mutualism. The moth does not just collect pollen, and unintentionally cross-pollinate the yucca in the process. It will continue to collect pollen until the female moth has a ball of pollen of the proper size, which she then forced into the pistal of the flower. At the same time, she injects her own eggs. This act insures the fertilization of the Joshua tree, and a plentiful supply of food for the larvae. When the moth larvae hatch they will eat the yucca seeds, although sparing enough to disperse for the next generation.
The Joshua tree is a dominant species in Mojave desert of southwest California, Nevada, Utah, and Arizona in the USA. Joshua trees are usually found between 2000-6000ft above see level. Most are found in the relatively flat areas of the high desert such as gently sloping alluvial fans in soils with good drainage. In addition to the Yucca moth mentioned above, many other animals use Yucca brevifolia as a home or resource for food.
- joshua tree Wikipedia
- joshua tree Desert USA
- joshua tree National Park Service
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- joshua tree San Francisco State University