The Biology Department has three greenhouses, an approximately 1,800 square foot roof-top museum collection, a 1,200 square foot roof-top research house, and a 1,300 square foot research house at the edge of campus. The museum collection contains a desert area, a wetlands section, and a rain forest section. Xeric (dry) adapted plants have many structural adaptations including stem succulence, vertical ribs that allow expansion or contraction as the water content increases or decreases, leaf succulence, and a dense covering of hair reflects sunlight and cuts down water loss. The spines and thorns on these plants almost certainly evolved in response to predation by thirsty desert animals. Many of the plants shown here are not closely related, rather in the process of adapting to arid regions these plants from several phylogenetic groups have converged on similar structural forms.