Broadly speaking, rice can be classified as being either Oryza sativa indica or Oryza sativa japonica. Varieties of both types are cultivated in Asia. Lon grained indica (xian) rices – of which there are many strains, are the most common.
PATNA RICE gets its name from Patna in India. At one time, most of the long grain rice sold in Europe came from Patna, and the term was used loosely to mean any long grain rice. The custome persists in parts of America, but elsewhere Patna is used to describe a variety of long grain rice from the Bihar region in India.
BASMATI RICE is a slender long grain rice that is grown in Northern India, in the Punjab, in parts of Pakistan and in the foothills of the Himalayas. After harvesting, it is aged for a year, which gives it a characteristic flavor ans a light, fluffy texture. The grains are long and slender, and become even longer during cooking, barmati rice has a cooling effect on hot and spicy curries.
THAI FRAGRANT RICE has a delicate but distinctive scent of jasmine, and is particularly highly prized.
SHORT-GRAINED JAPONICA (geng) rice are less fragrant, but tent to taste slightly sweeter than indicas. This type of rice is cultivated in Northern China, Japan, Korea, and surrounding areas. The rices are higher in amylopectin than long grains, and are therefore more starchy. The grains cling together when cooked, which makes them ideal for sushi and similar Japanese dishes.
GLUTINOUS RICE also known as sweet or waxy rice. It is even more sticky than Japanese short-grain rice. This endears it to Southeast Asian cooks, as the cooked rice can be shaped or rolled, and is very easy to pick up with chopsticks. White glutinious rice, with its common type, but there is also a black glutinous rice, which retains the husk and has a nutty flavor. A pinkish-red glutinous rice is cultivated on the banks of the Yangtze River, and a purple black variety has recently been developed. Glutinous rice has a high sugar content, and is udes in Japan for making senbei (rice crackers) and mochi (rice cakes), as well as sweet rice wine.
Source: Thai and Southeast Asian Cooking and Far Eastern Classics by Deh-Ta Hsiung, Becky Johnson and Sallie Morris