They eat the dried stems, leaves, flowers, and fruits of plants such as split grass, blazing star, gilias, desert dandelion, filaree and many other species. Lichens A lichen is two different organisms, an alga and a fungus, living together as a single unit in a symbiotic relationship. The alga provides food through photosynthesis and the fungus forms a support matrix and supplies the necessary water. Lichens are extremely resilient and able to withstand the wide extremes in temperature found in the desert. This attractively colored lichen is growing on a rock.
Lichens have four growth forms.
Yucca brevifolia Joshua trees, Yucca brevifolia , can be found in the most elevated areas of the Desert Tortoise Natural Area. These magnificent but incredibly slow-growing members of the lily family occcur throughout the Mojave desert. Indeed, the presence of Joshua trees is a useful indicator that an area is part of the Mojave desert biome. Joshua trees may reach a height of 30-35 feet. The beavertail cactus is a low growing member of the prickly pear family.