Dicotyledons with Incomplete Flowers — Cupitlifercz . 
IOI 
Distribution. —A Natural Order very numerous in species, though consisting of but few generic 
types; most abundant in the North Temperate zone and along the mountain chains of the Tropics, a 
few species extending into the South Temperate zone in South America. None occur in Tropical and 
Southern Africa. 
The Order is conveniently divided into two Tribes, distinguished thus :— 
I. OUERCINE/E.—Staminate flowers with a distinct perianth. Ovules 2, in each cell of the 
ovary. Examples : Oak (Qitercus), Chestnut ( Castanea ), Beech (. Fagus ). 
Number of British Genera 2 ; Species, 2. 
II. CORYLACE^E.—Staminate flowers destitute of a perianth. Ovary 2-celled, with one ovule 
in each cell. Examples : Hazel (Cory bus ), Hornbeam ( Carpinus ), Hop Hornbeam ( Ostrya). 
Number of British Genera, 2 ; Species, 2. 
I. OUERCINE^E. 
I. GENUS OAK ( Quercus ), including upwards of 250 species. Most numerous in species in 
Mexico, the United States, Asia Minor and the Levant, the Himalaya and Malayan Mountains, and in 
China and Japan. Common Oak ( Q . Robur ), the only species native in Britain, extends eastward 
through Europe to Central Asia. 
Diagnosis of the Genus. —Involucre (cupule) sheathing a single nut. Staminate flowers in 
interrupted catkins.' Ovary 3-celled. 
