The grapefruit tree is a subtropical citrus tree that grows between 4-14 metres. It is an 18th century hybrid first bred in Barbados, with a rounded top of spreading branches and evergreen, long ovate leaves measuring up to 15 centimetres long. The twigs normally bear short, supple thorns. It has white, 4-petalled flowers borne singly or clustered at the leaf axils, and an attractive round fruit approximately 10-15 centimetres wide with smooth peel in a pale lemon or pinkish glow. It is aromatic, with acidic bitter flesh that ranges from white to pink and deep-red, segmented with thin, membranous walls. Grapefruit are available both seedless and with seeds, sometimes housing up to 90 elliptical white seeds. The fruits thrive in warm subtopical climates such as Florida, and America is currently its largest producer of the fruit. It is also the producer of mutant strain of white grapefruit, Ruby Red.