484 BOTANY OF CROP PLANTS 



CITRUS SINENSIS (Common or Sweet Orange) 

 Description. — The sweet orange tree is 25 to 40 feet high, 

 round-topped, and usually bears slender, flexible, blunt 

 spines; the leaves are oval or ovate-oblong, and the petioles 

 are narrowly winged, articulated both with the blade and 

 the twig; i\iQ, flowers occur singly or in small cluster; the petals 

 are white above and below; there are from 20 to 25 stamens; 

 the ovary has 10 to 14 locules; the fruit is subglobular, light 

 orange to reddish, smooth, the pulp abundant and sweet, and 

 the juice sacks spindle-shaped. 



Geographical. — The sweet orange is the most widely cultivated of all 

 citrus fruits; it is probably a native of southeastern Asia. 



Types. — There are a number of groups or types of sweet 

 oranges; the four principal ones are Spanish oranges, Med- 

 iterranean oranges, blood oranges, and navel oranges. Spanish 

 oranges have large, coarse-grained fruit. Mediterranean 

 oranges are of good quaHty and fine-grained. Blood oranges 

 have red pulp or white pulp streaked with red; the fruit 

 is of good quaHty. Navel oranges are so named on account 

 of the umbilical mark at the apex of the fruit. This mark is 

 due to the protrusion of additional carpels developed within 

 the fruit. 



Uses. — Whereas oranges were once regarded as luxuries, 

 they are now produced in such quantities and sold at such 

 prices as to be within the reach of the majority of people. 

 Oranges are used mainly as a fresh dessert. Orange extract 

 is made by dissolving orange oil in strong alcohol. Up to the 

 year 191 1, almost the entire world's supply of orange oil 

 came from Sicily, Italy and adjacent parts of southern 

 Europe. Since then the West Indies have developed the 

 industry. 



The oil is used in the manufacture of perfumes, soaps, and 

 flavoring extracts, and to a sHght extent as a drug. 



