Today�s avocados are derived from three natural races. The Mexican type (semi-tropical) produces small fruits, 6 to 10 ounces having glossy purple, paper-thin skin when ripe. The Guatemalan type (subtropical) yields medium pear-shaped fruits which are first green, turning purple-black or coppery-purple when ripe, with a typically tough shell. The West Indian type (tropical) produces enormous, smooth, round, glossy green fruits as up to 2 pounds in weight