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CHAPTER XII 
RELATIONSHIPS OF 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, &c., 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, Hurope, China, Japan, and 
other parts of Asia. There are none in Africa south of 
the Mediterranean region, nor in South America or 
Australasia. Some remarkable species are found in the 
Himalayas, and many in the Malayan Archipelago. 
The various species of the genus Quercus are 
arranged into groups according to differences in the 
form and arrangement of the scales of the cupule, the 
characters of the leaves, and certain peculiarities in the 
acorns. Many oaks, especially those of warm countries, 
for instance, are ‘ evergreen, with hard, leathery leaves, 
quite unlike the leaves of our common British oak. 
