Saturday, November 23, 2013

Ginkgo

Readers can find a plethora of information on the Ginkgo on the WEB. This tree has been used medicinally for thousands of years and is now one of the top-selling items American herbal remedy stores (Mayo Clinic); they are also eaten as food. But be careful gentle reader, the Mayo Clinic lists only two or three diseases, out of nearly 100 claims of efficacy, that ginkgo has been firmly and scientifically proven to alleviate. Even these few ailments are not prevented, like some types of dementia and pain from clogged leg arteries. These diseases are perhaps equally well-treated by conventional medicines. Note that various Ginkgo tissues can be poisonous, depending on the dose and the part of the tree from which the herbal medicines are derived. The seeds are poisonous, but, as an enzyme in the seeds speeds up alcohol metabolism, were traditionally served with alcoholic drinks in Japan (Encyclopedia.com). People can also suffer various and potentially serious allergic reactions to Ginkgo. 
But the Ginkgo’s pharmacological potential is not what interests me most. Last week I was surprised to find a female Ginkgo at the Minnesota Landscape Arboretum. Females are not often planted because their fruit is messy and smells like rancid butter or vomit. Most Ginkgo trees you see in city parks are males, which can be propagated by grafting or grown from shoots. Look for these magnificent trees along major city boulevards.

The Ginkgo is a “living fossil.” Until one was discovered in 1690 in a Japanese temple garden, European botanists knew the tree only from 270-year-old fossils. Because of its high status in Buddhism and Confucianism, the tree was widely planted in Japan and Korea. Trees in those countries now found in the wild are so genetically uniform that they are generally believed to have escaped from cultivation (Wikipedia). 

Some temple trees are thought to be over 1500 years old. Ginko trees survived the bombing of Hiroshima and some of those trees live today. The tree has now been cultivated around the world and has been grown in the United States for the past 200 years. Nevertheless, in our country, the Ginkgo does not grow in the wild (Wikipedia).

Note the parallel veins in the leaf in the photograph below (taken several years ago at the Landscape Arboretum—the same tree, in fact, as in the first photo). Such venation is typical of primitive plants, as is the single split in the central part of the leaf. Their reproductive cycle is also primitive. Their exact relationship to other plants is uncertain, but may be most closely related to seed ferns (Wikipedia). They have no close living relatives.

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