Maple

Maples are trees or shrubs of the genus Acer. They are variously classified in a family of their

own, the Aceraceae, or (together with the Hippocastanaceae) included in the Sapindaceae. This is a

debate of very long standing, and Angiosperm Phylogeny Group favours a wide circumscription, as a

matter of style.

Maples are distinguished by opposite leaf arrangement. The leaves are usually palmately

lobed, although palmate compound, pinnate compound, pinnate veined or unlobed shapes occur. The

flowers are regular, pentamerous, and borne in racemes, corymbs, or umbels. Their distinctive

fruits occur in pairs, called keys (more generally known as samaras), shaped to spin as they fall

and carry the seeds a considerable distance on the wind. The derivation of the genus name "acer" is

uncertain, as it is a very old name. One of the options is that derives from the Latin acris

(sharp), from the hardness of the wood, supposedly used for spears in the past.

The leaves in most species are palmately veined and lobed, with 3-9 veins each leading to a

lobe, one of which is in the middle. Several species, including the Paperbark Maple Acer griseum,

Manchurian Maple Acer mandshuricum, Nikko Maple Acer maximowicziana, and Three-flower Maple Acer

triflorum, have trifoliate leaves. The Manitoba Maple (Acer negundo) has pinnately compound leaves

that may be simply trifoliate or may have 5, 7, or rarely 9 leaflets. One maple, the Hornbeam Maple

Acer carpinifolium, has pinnately-veined simple leaves that resemble those of hornbeams.

Maples flower in late winter or early spring, in most species with or just after the leaves

appear, but in some before them. Their flowers are small and inconspicuous, though the effect of an

entire avenue of maples in flower can be striking. They have five sepals, five petals about 1 to 6

mm long, 12 stamens about 6-10 mm long in two rings of six, and two pistils or a pistil with two

styles. The ovary is superior and has two carpels, whose wings elongate the flowers, making it easy

to tell which flowers are female. Within a few weeks to six months of flowering, the trees drop

large numbers of seeds.

Maples are important as cultivated ornamental plants, for syrup sources and timber

production. Some species have bright autumnal leaf coloring. The Sugar Maple (Acer saccharum) is

tapped for sap, which is then boiled to produce maple syrup or made into maple sugar or maple

candy. Quebec is the world's largest producer of maple sugar products. Sugar Maple wood, known as

hard maple, is the wood of choice for bowling pins, bowling alley lanes, and butcher's blocks.

Maples are an important early spring source of pollen and nectar for bees, especially

honeybees, which use its resources for spring buildup. Maples are used as a food plant for the

larvae of a number of Lepidoptera species (see List of Lepidoptera which feed on Maples).