The scientific name for a grapefruit tree is Citrus X paradisi. The name was altered in 1948 from Citrus paradisi when the grapefruit was found to be an accidental hybrid between a pummelo and an orange. Varieties include Duncan, Marsh, Flame, Red Blush, Texas Star Ruby, Melogold and Oroblanco.
Young grapefruit trees range from 15 to 20 feet in height. Older trees can grow as tall as 45 feet, with their circumference reaching as much as 8 feet. The pulp of the grapefruit is divided into 11 to 14 segments and can be pale yellow, white, pink or deep red.