DICOTYLEDONS: ARCHICHLAMYDE^ 299 



been developed, more for what are called dessert purposes 

 than for wine and raisins; and this culture has reached its 

 highest perfection in New York, New Jersey, Maryland, 

 Virginia, and Ohio. No cultivated plant is attacked by 

 more diseases than the grape, nor have any plant diseases 

 been more fully studied. 



(4) CITROUS FRUITS. These fruits all belong to a sin- 

 gle genus (Citrus), whose species are shrubs or small trees, 

 natives of tropical and subtropical Asia (China-India). 

 The citrous fruits are numerous, but the three forms chiefly 

 cultivated in the United States and common in markets are 

 as follows: 



Oranges are extensively cultivated in the United States 

 in central and southern Florida, the delta region of the 

 Mississippi, and California. All the varieties are derived 

 from a single species (Citrus Aurantium), and may be 

 grouped as bitter oranges and sweet oranges, the latter 

 being the chief market form. The very popular seedless 

 navel oranges of California were introduced in 1870 from 

 Brazil by the United States Department of Agriculture, 

 being a chance seedling variety. 



A closely allied species (Citrus nobilis) produces the 

 varieties of mandarin or kid-glove oranges. True mandarins 

 are small and light orange in color, and are not so much 

 prized in market as the dark orange or reddish forms known 

 as tangerines. 



Grape-fruits are extensively cultivated in Florida and 

 California, all* the varieties, most of which have originated 

 in Florida, coming from Citrus Decumana, a native of the 

 Malayan and Polynesian Islands. The original and best 

 name for this fruit is pomelo, although it is sometimes called 

 shaddock as well as grape-fruit. In reality, the pomelo or 

 grape-fruit is the common round-fruited form of the 

 markets, while the shaddock is a very different plant with a 

 pear-shaped fruit. 



