Wednesday, May 10, 2017
The Orange - 'Citrus sinensis' - fam: Rutaceae
Different names have been given to the many varieties of the genus. Orange applies primarily to the sweet orange Citrus sinensis(L.) Osbeck. The orange tree is an evergreen, flowering tree, with an average height of 9 to 10 mtrs (30-33 ft), although some very old specimens can reach 15 mtrs (49 ft). Its oval leaves, alternately arranged, are 4 to 10 cms (1.6-3.9 ins) long and have crenulate margins. Although the sweet orange presents different sizes and shapes varying from spherical to oblong, it generally has ten segments (carpels) inside, and contains up to six seeds (or pips), and a porous white tissue – called pith or, more properly, mesocarp, or albedo, lines its rind.
When unripe, the fruit is green. The grainy irregular rind of the ripe fruit can range from bright orange to yellow-orange, but frequently retains green patches or, under warm climate conditions, remains entirely green. Like all other citrus fruits, the sweet orange is non-climacteric. The Citrus sinensis group is subdivided into four classes with distinct characteristics: common oranges, blood or pigmented oranges, navel oranges, and acidless oranges.
Other citrus groups also known as oranges are:
Bitter orange Citrus aurantium, also known as Seville orange, sour orange (especially when used as rootstock for a sweet orange tree), bigarade orange and marmalade orange. Like the sweet orange, it is a pomelo x mandarin hybrid.
Bergamot orange Citrus bergamia Risso, grown mainly in Italy for its peel, producing a primary essence for perfumes, also used to flavour Earl Grey tea. It is a hybrid, probably bitter orange x limetta.
Trifoliate orange Poncirus trifoliata, sometimes included in the genus, classified as Citrus trifoliata. It often serves as a rootstock for sweet orange trees and other Citrus cultivars.
Mandarin orange Citrus reticulata is an original species of citrus, and is a progenitor of the common orange. An enormous number of cultivars have, like the sweet orange, a mix of pomelo and mandarin ancestry. Some cultivars are mandarin-pomelo hybrids, bred from the same parents as the sweet orange (e.g. the tangor and ponkan tangerine).
Other cultivars are sweet orange x mandarin hybrids, e.g. clementines. Mandarin traits generally include being smaller and oblate, easier to peel, and less acidic. Pomelo traits include a thick white albedo (rind pith, mesocarp) that is more closely attached to the segments. 1
REFERENCES: Wikipedia 1