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A TEXTBOOK OF THEORETICAL BOTANY 



probability in the Carboniferous. It survived in Britain until the middle 

 Tertiary. During the Jurassic period it reached its greatest abundance and 

 almost world-wide distribution, aided probably by the prolonged resistance 

 of the seeds to immersion in sea water, but it has declined progressively since 

 that time and is now only found apparently wild in one or two places in the 

 mountains of western China. Indeed until 1S99 it was known only as a 



Fig. 735. — Ginkgo bilobo. A tree in a temple in 



western China. 



(From a photograph by E. H . Wilson.) 



\ 



cultivated plant in China and Japan, where it has been grown from time 

 immemorial as a temple tree (Fig. 735). Until the discovery of wild specimens 

 it was supposed to have owed its preservation from extinction to this cause. 

 Actually its popularity in the East has led to its being planted very widely 

 elsewhere during the last two hundred years. It forms a graceful, strictly 

 pyramidal tree, reported to reach nearly 100 ft. in China but rarely half that 

 height in Britain. With age it acquires a rounded head by the upgrowth 

 of the branches. It is quite hardy and is not uncommon in English gardens, 

 where it forms a decorative small tree with fine autumn colouring. Most 

 of the trees of flowering age in Britain are males, but the few females produce 



