The Black Sugar Maple is considered by some authorities to be a subspecies of the Sugar Maple, Acer saccharum and the plant will be found listed as Acer saccharum Marshall subsp. nigrum (F.Michx.) and sometimes as Acer nigrum x saccharum or simple as Acer saccharum nigrum. Minnesota authorities treat the tree as a separate species.
Black Sugar Maple is a native deciduous tree with a dense rounded crown, growing 60 to 80 feet high with a trunk diameter of 2 to 3 feet. The bark is dark gray to blackish becoming thick with age into deeply furrowed plates.
The twigs are brown and slender when young with numerous light colored lenticels. The younger shoots will be green with some fine hair. Buds are reddish-brown with some green and with fine hair. Terminal buds are multiple, usually 3 with the center bud much larger, and the lateral buds on the twig are fairly tight to the twig.
The leaves are opposite, 4 to 5-1/2 inches long and wide, with 3 (sometimes 5) broad long-pointed lobes. The lobe sinuses are rounded but the sinuses of the lower lobes are more closed than those of Sugar Maple. The edges are wavy and usually drooping and sometimes there are a few blunt teeth. Main leaf veins all rise from the base. The upper surface is a dull green, but darker than the Sugar Maple, the lower surface paler with some soft hairs on and near the veins. The leaf stalks may have some fine hair. Fall color is a deep yellow to yellowish orange.
Flowers: The tree can be monoecious, that is with separate male and female flowers or dioecious, with the flowers on different trees. Male flowers (staminate) are in drooping umbels (tassel-like clusters) up to 3 to 4 inches long, on hairy stalks. Each cluster will have 8 to 14 flowers and each individual flower is only about 1/8 inch long with a 5-toothed yellow-green calyx and around 6 to 8 stamens, no petals. The female flowers (pistillate) are also in drooping clusters, but shorter, 1 to 2 inches long. They are the same size and color as the male flowers but with the ovary and a divided style. Both flowers appear with the leaves and when monoecious, can be together in the same cluster. Flowers are wind pollinated.
Seed: Female flowers mature to a one-seeded samara, about 1 inch long, with a broad wing that is paired with another forming an angle of 45 to 90 degrees, green initially and turning light brown. These mature in late summer, drop from the tree in the autumn and are wind dispersed. It usually takes 30 to 40 years for a tree to produce a quantity of seed.
Habitat: Black Sugar Maple grows in moist to mesic soils that are well drained, full sun to light shade. The root system is shallow and branching. The foliage is thick and produces thick shade.
Names: The genus, Acer, is the Latin word for 'maple'. The species name, nigrum means 'black'. The author name for the plant classification, ‘F.Michx.’ is for Francois Andre Michaux (1770-1855) French botanist, son of botanist Andre Michaux. He traveled with his father in the United States and his monumental work incorporating his father’s notes was a 3-volume work - The North American Sylva, 1817-1819. Botanists have recently moved the maples into the Sapindaceae family from the older Aceraceae family.
Comparisons: The distinction between the Sugar Maple, Acer saccharum, and the Black Sugar Maple is something botanists like to argue over. The characteristics of the two trees overlap and the sap of both is used for syrup. The bark may be blacker on Black Maple, but not always. The leaf tends to have wavy droopy edges with more taper to the lobes and the lower sinuses are almost closed. The samaras tend to be a bit more divergent. Other than that you may not see the difference.
Above: The Black Sugar Maple has a dense rounded crown. In close quarters with other trees it will be less broad near the base.
Below - Leaves: Leaves have 3 (sometimes 5) broad long-pointed lobes. The lobe sinuses are rounded but the sinuses of the lower lobes are more closed than those of Sugar Maple. The edges are wavy and usually drooping and sometimes there are a few blunt teeth.
Below: 2nd photo - The lower surface paler with some soft hairs on and near the veins.
Below: 1st photo - The bark is dark gray to blackish becoming thick with age into deeply furrowed plates. 2nd photo - Twigs are reddish-brown with light lenticels. Lateral buds are tight to the twig, terminal buds are usually 3 with the center one larger. 3rd photo - The samaras are paired with another forming an angle of 45 to 90 degrees.
Below: Leaf comparison of common maples. Images not to scale.
Notes: Black Sugar Maple has been in the Garden since before the time of Martha Crone's 1951 census. Gardener Cary George reported planting a few in 1994. In Minnesota it is found in the counties of the SE section of the state. In North America Minnesota is the western edge of the range, extending south and east from the Mississippi. In Canada it is known in Ontario and Quebec.
Eight species of Maple are found in the wild in Minnesota: A. negundo, Box Elder; A. nigrum, Black Maple; A rubrum, Red Maple; A. saccharinum, Silver Maple; A. saccharum, Sugar Maple; A. spicatum, Mountain Maple; A. ginnala, Amur Maple and A. platanoides, Norway Maple. The latter two are not native but introductions that have naturalized.
Uses: Like the Sugar Maple, the wood is tough, hard, heavy and strong wood, used for furniture, flooring, panels, veneer, tool handles and other wooden ware requiring a hard wood. And like the Sugar Maple the sap is used in the production of Maple Syrup.
References: Plant characteristics are generally from sources 1A, 32, W2, W3, W7 & W8 plus others as specifically applied. Distribution principally from W1, W2 and 28C. Planting history generally from 1, 4 & 4a. Other sources by specific reference. See Reference List for details.
Identification booklet for most of the flowering forbs and small flowering shrubs of the Eloise Butler Wildflower Garden. Details Here.
Friends of the Wild Flower Garden, Inc. Text and photos are by G. D. Bebeau unless otherwise credited. "www.friendsofthewildflowergarden.org"