Red maple (Acer rubrum) is also known as swamp maple or soft maple. It is one of the most common and widely spread deciduous trees of Eastern North America, ranging from Lake of the Woods to Newfoundland and south to Florida.
Red maple is adaptable to a wide range of site conditions and can be found growing in both swamps and on poor dry soil and anywhere in between, however it is often out-competed by sugar maple (Acer saccharum) on mesic sites. Red maple is a medium sized tree, reaching heights of 25 meters and a diameter of almost a meter, and can live over 100 years.
The leaves of the red maple are the easiest way to distinguish it from other maples. Like other maples, they are deciduous and oppositely arranged on the twig. The leaf of red maples are typically 5-15 cm long and equally wide with 3-5 irregularly toothed lobes (in contrast, the leaves of Acer saccharinum are much more deeply notched and characteristically have 5 lobes.) The upper side of the leaf is light green and the underside is whitish. The leaf stalks are usually red, as are the twigs. The leaves turn a brilliant red in autumn.
The twigs of the red maple are red to greyish-brown and hairless. Dwarf shoots are present on many branches. In winter, the twigs bear clusters of flower buds, easily seen from a distance. The twigs of red maple are almost impossible to distinguish from those of silver maple (Acer saccharinum), except that the later have an unpleasant odour when bruised. These two species also frequently hybridize to make an intermediate species known as Freeman's maple (Acer xfreemanii).
Red maple flowers are of two types. The seed, or female flowers are red with 5 very small petals and sepals borne in clusters, usually at the twig tips. The pollen or male flowers are nothing more than yellow stamens protruding from dwarf shoots on the branches. Both types of flowers are found on the same tree, but young trees may only produce one type.
The fruits, or samaras of the red maple are variable in colour from red to brown to yellow and are 15-25 mm long and borne in pairs at an angle of 50-60 degrees. They mature in late May or early June.
The sap of the red maple can be used to produce syrup or sugar, but it is less sweet than that of the hard or sugar maple.