CHAPTER XII. 



RELATIONSHIPS OP THE OAKS THEIR DISTRIBUTION" 

 IN SPACE AND TIME. 



THE oak is a member of a very large and ancient 

 group of dicotyledonous flowering plants, embracing the 

 beeches, chestnuts, hazel-nuts, etc., and many other 

 forest trees of the Northern Hemisphere. 



The number of species of oaks ( Quercus) is very large, 

 probably more than 300, of which the majority belong 

 to North America, Europe, China, Japan, and other 

 parts of Asia. There are none in Africa south of the 

 Mediterranean region, nor in South America orA ustral- 

 asia. Some remarkable species are found in the Hima- 

 layas, and many in the Malayan Archipelago. 



The various species of the genus Quercus are ar- 

 ranged into groups according to differences in the form 

 and arrangement of the scales of the cupule, the charac- 

 ters of the leaves, and certain peculiarities in the acorns. 

 Many oaks, especially those of warm countries, for in. 

 stance, are " evergreen," with hard, leathery leaves, quite 

 unlike the leaves of our common British oak. 



The latter is denominated botanically as Quercus 



