The Mojave Desert covers parts of California, Nevada, Arizona and Utah. The lowest elevation (282 feet below sea level) in the United States and the hottest temperature (134 degrees F) occur in Death Valley. The topography consists of sand and gravel, salt flats and sparse vegetation. Some of this vegetation occurs nowhere else in the world.
Joshua trees (Yucca Brevifolia) thrive in the Western Mojave Desert. The name Joshua tree came from the Mormon pioneers who said it reminded them of the biblical leader Joshua raising outstretched arms toward the heavens. The slow-growing evergreen reaches heights of 16 to 49 feet. The Joshua tree usually grows as a single-stemmed plant, but two- and three-stemmed plants also exist. Gray-green spiny-tipped leaves grow to 16 inches long and 1 inch wide, clustered near branch ends. Joshua tree often grows in groves on slopes, plains and mesas. Originally classified as a member of the agave family, Joshua tree was reclassified as a member of the lily family.
Pinyon pine (Pinus monophyllla) grows 20 to 40 feet tall. The needles on pinyon pine grow 3/4 inch to 1 1/2 inch long and live 5 to 12 years allowing the tree to conserve nutrients. Pinyons live to 400 years old and have been known to reach 800 to 1,000 years old. The cones grow to 2 inches and contain edible seeds. The seeds provide food for several songbirds, quails, squirrels, chipmunks, black bears and mule deer. Native Americans depended on pinyon pine for their diet, and the seeds were eaten raw, roasted and ground into flour. The needles were steeped for tea. In the United states, the seed crop is only second to pecans. The annual harvest exceeds 1 million pounds of seed, and the uses are in making candies, cakes and cookies. The pine cones are crushed for incense.
The native yucca (Yucca schidigera) occurs treelike or shrublike only in the higher elevations; on dry rocky slopes, mesas, sandy desert and washes of the Mojave Desert and nowhere else in the world. The sparingly branched plants grow slowly from 9 to 15 feet and sometimes to 30 feet with gray-brown bark. Yuccas live for hundreds of years. The yucca moth pollinates the yucca plants. During years when this pollinator may not be available, sexual reproduction of the yucca might not occur.