Maple

Maples are trees of the genus Acer in the order Sapindales, variously classified in the family Aceraceae, Hippocastanaceae, or Sapindaceae. Their distinctive key, or samara, which contains the seeds, is designed to whirl as it falls and occasionally be carried great distances by the wind.

Maples bloom in late winter or early spring, in some species before the leaves appear. Their flowers are small and inconspicuous, though the effect of an entire avenue of maples in bloom can be striking. They have five sepals, five petals about 3 mm long, twelve stamens about 1 cm 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 of blooming, the trees drop large numbers of seeds.

The leaves in most species are palmately[?] veined, with 3-9 veins, one of which is in the middle. Several species, including the paperbark maples, Acer griseum, Manchurian maple, Acer mandshuricum, Nikko maple, Acer nikoense, and three-flower maple, Acer triflorum, have trifoliate[?] leaves. The box elder (Acer negundo) has pinnately compound leaves that may be simply trifoliate or may have 5, 7, or even 9 leaflets. One maple, the hornbeam maple, Acer carpinifolium, has pinnately-veined leaves that resemble those of the hornbeam.

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.

The flag of Canada depicts a maple leaf.

---

A draft synopsis of the family Aceraceae:

http://hua.huh.harvard.edu/china/mss/volume11/Aceraceae-AGH_coauthoring.htm