Where does sugar come from?

Most of the world’s sugar comes from sugar cane, a giant grass that looks like bamboo.  It’s stems are filled with a sappy pulp, 90% of which is juice.  After processing, it is transformed into syrups or crystals from which various sugar products are made.
 
Beet sugar, the world’s second major source of sugar, accounts for about 2/5 of the world’s sugar production.  Beet sugar comes from a variety of beet named Beta vulgaris.  Its root contains a high concentration of sucrose. 
 
Source(s):
The Oxford Companion to Food by Alan Davidson, 2006.
Answers.com  “Sugar Beet”