The Ruby variety was introduced from the Mediterranean (country unknown) to Florida about 1880 and brought to California not long thereafter. From its appearance and behavior, it may prove to be an old Italian variety. The development of blood coloration in Ruby is variable and for this reason, it has not become a popular variety. In California's coastal region, it never develops red pigmentation. Ruby is at its best in hot interior districts, however under these conditions the pigmentation is still variable. Ruby has since been used as a parent variety in the development of new varieties of citrus and it has been found that although Ruby itself is poorly colored, its progeny tends to be very highly colored.