Limes are divided into two groups, acid and sweet.  The acid limes are the type grown in the United States, while the sweet limes are popular in many other citrus growing countries.

The Acid limes are divided into Tahiti and Mexican types.

The Tahiti group is characterized by large fruit that is grown on larger, cold resistant trees than that of the Mexican group.  Tahiti Group  include the Persian, Bearss, Idemore, and Pond.  

The Mexican type is considered the true type of the species.  The fruits are small with very thin rinds.  There are small differences in the varieties of this group. In Florida this type is called Key, the same type in Mexico, California, Texas, and Arizona, is called Mexican.  The Dominican Republic calls this type the Dominican, and in the West Indies called West Indian.  The fruit is larger than the Key Lime when grown in the deeper soil of the mainland.