480 BOTANY OF CROP PLANTS 



Petals white both on the inside and outside. 

 Leaves wingless or narrowly winged. 



Fruit small, 1 J-^ to 2j^' inches in diameter, its skin thin, C. aurantifoUa 



(lime). 

 Fruit large, its skin thick. 

 Tree small, 12 to 20 feet tall; skin of fruit easily removed, C. nobilis 



(king orange). 

 Tree large, 20 to 40 feet high; skin of fruit not easily removed, C. 

 sinensis (common sweet orange). 

 Leaves broadly winged. 



Fruit large, pale lemon-yellow when ripe, C. grandis (grapefruit, pomelo, 



shaddock). 

 Fruit medium-sized, orange-colored or reddish when ripe, C. aurantium 

 (sour or Seville orange). 



CITRUS MEDICA (Citron) 



Description — This is a shrub or small tree with short, 

 stout thorns; the leaves are large, crenate or serrate, and its 

 petioles are wingless; the large flowers are usually in clusters 

 of 3 to 10; their petals are white above, and reddish purple 

 below; the stamens are as many as 30 or 40; the ovary usually 

 has from 9 to 10 locules; the fruit is large, 6 to 9 inches long, 

 rough or warty, lemon-yellow when ripe, its skin thick, the 

 pulp scarce and very acid, and the juice sacks small and 

 slender. In the "fingered citron," the fruit segments are 

 separated into a number of finger-like projections. 



Geographical. — This species is probably a native of India. It is cultivated 

 most extensively in the Mediterranean region, and to some extent in this 

 country. 



"Citron." — The commercial "citron" is the dried fruit'of 

 Citrus medica. Before the fruit is candied, it is placed in 

 brine to extract the xmdesirable oil in the skin. The fruit 

 is then boiled for an hour or so in a sugar solution to which 

 has been added some glucose. The glucose prevents the 

 product from becoming too brittle. It is then allowed to 



