UCR's academic colleges administer significant museum collections in the arts and sciences. The Citrus Variety Collection constitutes 1,800 trees representing two of each of the 640 types of citrus and 28 other related genera in the family Rutaceae, the largest such collection in the world. The Herbarium houses more than 110,000 dried plant specimens from across the Western hemisphere. UCR is also home to of botanical gardens containing more than 3,500 plant species from around the world. The Gardens are located in the eastern foothills of the Box Springs Mountain on the University of California, Riverside campus. Over four miles (6 km) of trails wind through many microclimates and hilly terrain.