Several beautiful specimens of three-flowered maple (Acer triflorum) grow in front of the Hunnewell Building. While many maples have simple leaves (think sugar maple or red maple), A. triflorum has compound leaves composed of three leaflets. This maple develops excellent orange to red fall color and has attractive amber bark that exfoliates in narrow curls.

Just across the road from the Hunnewell Building is the original specimen of Acer rubrum ‘Schlesingeri’, a red maple cultivar introduced by the Arnold Arboretum. It is one of the earliest red maple cultivars to show fall color, often as early as mid to late August.

The genus Acer holds a number of interesting examples of North American–Asian disjunct flora (closely related, similar-looking species that grow on separate continents). Among the Arboretum’s maples, note the similarities between the striking stripe-barked or snake-bark maples from Asia (including A. tegmentosum, A. davidii, and A. capillipes) and striped maple (A. pensylvanicum) from eastern North America.

The maple collection holds accessions of Japanese maple (Acer palmatum) and its cultivars, which are popular small ornamental trees. Similarly handsome species in the collection include Korean maple (A. pseudosieboldianum), full moon maple (A. japonicum), painted maple (A. mono), and hairypalm maple (A. pubipalmatum).

Paperbark maple (Acer griseum) has long been favored by plant connoisseurs for its lovely exfoliating, cinnamon-colored bark and bright red-orange fall color. The Arboretum holds two of the first paperbark maples in the United States, grown from seed wild-collected in China by E. H. Wilson in 1907; look for one venerable specimen in the heart of the maple collection, and a unique, wide-spreading specimen in the Explorers Garden on Bussey Hill.