A current advertising blitz has introduced the American public to Ginkgo biloba, easily recognized from its distinctive fan-shaped (flabelliform) leaves. In botany textbooks ginkgo, also called the maidenhair tree, is often described as a "living fossil"--the oldest living seed plant--because leaf impressions of presumably this same species have been found in sedimentary rocks 150 million years old! A mere fifty million years ago (during the Eocene Epoch), when global climate was much milder, this species even grew in the northern forests of Alaska. Today, however, the only wild populations of this deciduous tree occur in eastern Asia.
For thousands of years in China and Japan, ginkgo was widely planted around religious temples. In those same regions ginkgo wood, hard and medium in color, has been used for decorative purposes.
This species of gymnosperm has separate male and female plants, and ginkgo is one of the few plant species in which there are sex chromosomes, as in animals. In MEMBG, a male plant grows on the slope with the conifers, and a female plant shades The Nest. Most horticulturists recommend that only males be planted, either from grafted trees or cuttings from known male plants. The reason is that the fleshy female seeds, as they rot on the ground in early fall, produce a rancid odor. Ginkgo seeds are avidly collected, however, because the kernel, once separated from the smelly outer flesh and roasted or boiled, is considered an Asian delicacy--generally known as ginkgo nuts.
Why all the recent fuss about Ginkgo biloba? This species, and in particular its peculiar seed, produces a long list of unique organic compounds, including bilobol, ginkgol, ginnol, and ginkgolic acid. In eastern Asia, the ginkgo seed has been used in traditional medicine for treating a wide variety of ailments, including asthma, coughs, pulmonary tuberculosis, and bladder irritability. In the United States, Ginkgo biloba is being marketed as an herbal stimulant and, potentially, a way to improve memory, as possibly shown in recent trials with Alzheimer's patients. One hypothesis is that ginkgo, like aspirin and ginseng, may "thin" the blood, and thereby promote better circulation.