Rice:  A Grass that feeds the World

Rice is the seed of the grass species Oryza sativa (Asian rice) or Oryza glaberrima (African rice). First used in English in the middle of the 13th century, the word "rice" derives from the Old French ris, which comes from Italian riso, in turn from the Latin oriza, which derives from the Greek ὄρυζα (oruza).  
 Rice, a monocot, is normally grown as an annual plant, although in tropical areas it can survive as a perennial and can produce a ratoon crop for up to 30 years. As a cereal grain, it is the most widely consumed staple food for a large part of the world's human population, especially in Asia. It is the agricultural commodity with the third-highest worldwide production, after sugarcane and maize, according to 2012 FAOSTAT data.
 Wild rice, from which the crop was developed, may have its native range in Australia. Chinese legends attribute the domestication of rice to Shennong, the legendary emperor of China and inventor of Chinese agriculture. Genetic evidence has shown that rice originates from a single domestication 8,200–13,500 years ago in the Pearl River valley region of Ancient China.
From East Asia, rice was spread to Southeast and South Asia. Rice was introduced to Europe through Western Asia, and to the Americas through European colonization. In 1694, rice arrived in South Carolina, probably originating from Madagascar. There are numerous stories about how the rice came to North America, including a slave smuggling grains in her hair and a ship driven in to trade by a storm.
In the United States, colonial South Carolina and Georgia grew and amassed great wealth from the slave labor obtained from the Senegambia area of West Africa and from coastal Sierra Leone. At the port of Charleston, through which 40% of all American slave imports passed, slaves from this region of Africa brought the highest prices due to their prior knowledge of rice culture, which was put to use on the many rice plantations around Georgetown, Charleston, and Savannah.
From the enslaved Africans, plantation owners learned how to dyke the marshes and periodically flood the fields. The predominant strain of rice in the Carolinas was from Africa and was known as 'Carolina Gold'. The cultivar has been preserved and there are current attempts to reintroduce it as a commercially grown crop. You can see it growing here in the Garden of Discovery.
One of the earliest known examples of companion planting is the growing of rice with Azolla, the mosquito fern, which covers the top of a fresh rice paddy's water, blocking out any competing plants, as well as fixing nitrogen from the atmosphere for the rice to use. The rice is planted when it is tall enough to poke out above the azolla. This method has been used for at least a thousand years.
There are many varieties of rice and culinary preferences tend to vary regionally. In some areas such as the Far East or Spain, there is a preference for softer and stickier varieties.