The namesake for this national park is the Joshua tree. The largest of the yuccas can reach a height of 40 feet. It is indigenous only to the Mojave Desert. The spikey evergreen can live over 150 years. This odd-shaped yet picturesque member of the agave family has several names. The Cahuilla Indians called it hunuvat chiy’a or humwichawa. The scientific name is yucca brevifolia. In the mid-19th century, the Mormons observed the outstretched limbs resembled the Biblical Joshua leading the Israelites during the Exodus. They named it the Joshua tree.