A Living Fossil

Location:  Between gates of faculty parking ot

This is a Ginkgo tree, Ginkgo biloba.  This native of China is the only living species of the Family Ginkgoaceae.  But as long as 270 million years ago many similar trees belonging to several species of Ginkgo were living in North America, a fact that is documented by thousands of fossils of the very distinctive leaves (and other plant parts).  For many years botanists thought Ginkgo was extinct, not only in North America but in all parts of the world.  But in 1691 a German botanist, Engelbert Kaempfer, discovered living Ginkgo trees in Japan and eventually whole forests of them were found in remote areas of China!
    
The trees belong to a large group of plants called Gymnosperms.  Members of this group include the more familiar Pine, Spruce, Fir, Hemlock, etc. most of which have cones rather than flowers as their reproductive organs.

The tree's branches tend to be produced in whorls more like Pine trees rather than the more random branching patterns of Angiosperm (flower-producing) trees like Maple, Ash, etc.  Ginkgo produces two kinds of branches:  long branches and very short, spur branches that grow on the sides of the long branches.

Ginkgo trees are either male or female.  This is a male tree with male reproductive organs that produce pollen in Spring.  Female trees produce the seeds which have a fleshy coat.  This fleshy seed smells very bad.  Its odor has been described as the odor of rotting dog vomit!  The Ginkgo is a very nice tree for the home landscape.  It is also used extensively in city streetscapes because it is very resistant to auto emissions and suffers little insect damage.  But if you plant it near your home, you must be sure to plant only male trees so as to avoid the smelly seeds.  The sex of the tree can be determined by examining the chromosomes of root cells.
-- David Kramer
 

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