1. The ginkgo tree, also called the MAIDENHAIR TREE (Ginkgo biloba), is the only living representative of the order Ginkgoales. The ginkgo tree, native to China, is often termed a living fossil because it is unclear whether uncultivated groups of ginkgo trees can be found in the wild.|
It has been planted since ancient times in Chinese and Japanese temple gardens and is now valued in many parts of the world as an attractive, fungus- and insect-resistant ornamental tree. It tolerates cold weather, and unlike most gymnosperms, can survive the adverse atmospheric conditions of urban areas.
|A ginkgo tree is pyramidal in shape, with a columnar, sparingly branched trunk up to 30m (100 feet) tall and 2.5m (8 feet) in diameter. The fissured bark is grayish, deeply furrowed on older trees and has a corky texture. Fan-shaped ginkgo leaves resemble the leaflets of the maidenhair fern and are borne on short, spurlike but greatly thickened shoots. The leathery leaves are up to 8 cm (3 inches) long and are sometimes twice as broad. Two parallel veins enter each blade from the point of attachment of the long leafstalk and fork repeatedly toward the leaf edges. Most leaves are divided into two lobes by a central notch. Dull gray-green to yellow-green in summer, they turn golden yellow in autumn, remaining on the tree until late in the season, and then fall rapidly.|
Male microsporangia (pollen-forming structures) and female ovules are borne on separate trees. Pollen grains are carried to the female trees by the wind.|
Female trees bear paired ovules, which, when fertilized, develop into yellowish, plumlike seeds about 2.5 cm(1 inch) long, consisting of a large nut surrounded by a fleshy outer covering. The nut is silvery in color (the word ginkgo is derived from the Chinese and Japanese words for silver nut or silver apricot) and when roasted is considered a delicacy. The ripened fleshy covering has a very disagreeable odor, making the female tree less popular for garden planting.