OAK FAMILY 
and increase in productiveness as they grow older. The 
entire family is especially subject to attacks of the gall-fly. 
Quercus belongs to the long-lived trees ; the life of some 
species is believed to reach one thousand years, There are 
of course no records of long life in America, but there are 
oaks in England which are believed to have been old trees in 
the time of William the Conqueror. Pliny mentions a Quer- 
cus Ilex which was an old tree when Rome was founded and 
which was still living in his time. In the United States the 
largest specimens of the genus are found in the Mississippi 
valley. 
Remains of oak trees are found far north of their present 
home in the miocene and eocene rocks of North America. 
American oaks naturally divide themselves into groups 
which are characterized by the shape of their leaves and the 
time required to bring their fruit to maturity. 
The first division comprises those species whose leaves 
have either rounded lobes or are sinuate toothed, or entire, 
but are destitute of bristles. These bloom in the spring and 
mature their acorns the same season. They are called 
the White Oak Group, or the Annuals. The White, Post, 
Bur, Swamp White, Chestnut, Yellow, and Chinquapin are 
Annuals, 
The second division comprises those species whose leaves 
have pointed lobes which terminate in bristles. These 
bloom in the spring, but the acorn does not mature until the 
autumn of the following year. They are called the Red Oak 
Group, or the Biennials. The Red, Scarlet, Black, Spanish, 
Pin, Bear, Black Jack, Shingle and Willow are Biennials, The 
leaves of the Shingle and the Willow oak are destitute of 
bristles, but the acorns mature the second year. 
