Orange

Orange—specifically, sweet orange—refers to the Earth citrus tree Citrus sinensis and its fruit. The orange is a hybrid of ancient cultivated origin, possibly between pomelo (Citrus maxima) and tangerine (Citrus reticulata). It is a small tree, growing to about 10 m tall, with thorny shoots and evergreen leaves 4-10 cm long. Oranges originated in southeast Asia, in either India or modern day Pakistan, Vietnam or southern China. The fruit of Citrus sinensis is called sweet orange to distinguish it from Citrus aurantium, the bitter orange.

Doctor Who references

• Oranges grew in the warm Mediterranean climate of the Duchy of San Martino in 15th century Italy. Sarah Jane Smith was picking and eating oranges when she was captured by members of the Cult of Demnos ("The Masque of Mandragora").

• Before taking her to the Palace Theatre, the Doctor promised Leela, "if you're very good, I'll buy you an orange." At the time of the events of "The Talons of Weng-Chiang," oranges and most other fruit were rare treats, due to their perishable nature and the lack of practical refrigeration and pesticides. They were often purchased as gifts for ladies and children, especially at Christmas.

• Like all citrus fruits, oranges are rich in citric acid, a precursor to vitamin C. As such, they would not have been on the menu for Cessair of Diplos, for whom citric acid was toxic, a fact discovered by Romana and Professor Rumford during the events of "The Stones of Blood."