RUE FAMILY (RUTACEAE) 



100. China, sweet orange 



Sweet orange, or orange, the best known and 

 most popular of the citrus fruits, is distinguished 

 by : ( 1 ) the familiar, usually smooth orange roimd 

 fruit, mostly 21/0-314 inches in diameter, with 

 sweetish orange-colored flesh; (2) very fragrant 

 white flowers with usually 5 petals about 11/4-11/4 

 inches across; and (3) leaves oblong to elliptic or 

 ovate, short-pointed or rounded at both ends, and 

 with narrowly winged petiole. 



An evergreen small tree becoming 20-30 feet 

 tall and 6-10 inches or more in trunk diameter, 

 with rounded crown. The bark is brown and finely 

 fissured, the inner bark yellowish and slightly bit- 

 ter. The light green angled twigs usually have 1 

 slender sharp spine i/g hich long at a node. 



The alternate leaves have a green petiole %-% 

 inch long, jointed to the blade. The leaf blade is 

 21/2-6 inches long and II/4-3I/2 inches wide, the 

 edges usually with many minute rounded teeth, 

 slightly leathery and with numerous tiny gland 

 dots, above dark green to yellow green and slightly 

 shiny, and beneath dull light green. 



Flowers are lateral, 1-6 at base of a leaf. There 

 is a greenish-white broad saucer-shaped calyx % 

 inch high and 5-toothed; usually 5 white elliptic 

 petals 1/2-% inch long, gland-dotted and slightly 

 fleshy, spreading and turned back; 20-25 white 

 stamens I/2 inch long with brown anthers, united 

 into ring at base; and on whitish disk a pistil % 

 inch long with 10-13-celled yellow-green rounded 

 ovary, slender style, and rounded stigma. 



The familiar sweetish orange fruit (beriy) has 

 a smooth usually thin peeling less than 14 inch 

 thick, orange at maturity (but the fruit is some- 

 times consumed while still green), and solid center 

 of orange-colored juicy flesh which is sweet or 

 sometimes slightly sour. Seeds are white and 

 wrinkled. The navel orange is a variety distin- 

 guished by the fruit apex not completely covered 

 by the outer rind but with additional small seg- 

 ments or cells and usually is seedless. Flowering 

 in spring and maturing fruits in the fall, but in 

 some areas the fruits may persist on the trees into 

 the following May. 



Citrus sinensis Osbeck* 



The wood is light yellow, hard, strong, and 

 tough, and very susceptible to attack by dry-wood 

 termites. Its uses includes canes and various small 

 articles, such as manicure sticks. 



The orange, witli its high vitamin C content, is 

 one of the most popular tropical fniits. Quanti- 

 ties of the sweetish juice are canned in Puerto 

 Eico for export. The peel yields an essential oil 

 when pressed and sometimes is candied. Orange 

 oil is official in the United States Phai'macopoefa 

 as a flavoring agent. 



Grown extensively as a fruit tree in Puerto Rico, 

 where it is one of the most important fruits and 

 also a good honey plant. The trees are also orna- 

 mental. Found throughout the island but chiefly 

 in cofi'ee plantations in the lower Cordillera and 

 moist limestone regions. Also in Mona, St. Croix, 

 and St. Thomas, and probably othei-s of the Vir- 

 gin Islands. Occasionally escaping from cultiva- 

 tion or naturalized. 



Public forests. — Cambalache, Carite, Guaja- 

 taca, Guilarte, Luquillo, Maricao, Rio Abajo, Toro 

 Negro. 



Municipalities where especially common. — 

 5, 6, 8, 21, 32, 47, 61, 70, 73. 



Range. — Probably originally native of China, 

 Vietnam, or other southeastern Asiatic regions 

 but no longer known as truly wild. Widely culti- 

 vated in tropical and subtropical regions, escaping, 

 and becoming naturalized. Bermuda, throughout 

 West Indies, and subtropical United States from 

 Florida to California, south to Argentina. 



Other common names. — china dulce (Puerto 

 Rico) ; naranja, naranja dulce (Spanish) ; naranja 

 de China (Dominican Republic, Cuba, Nicara- 

 gua) ; naranjo, naranjo comun, chino dulce (Vene- 

 zuela) ; sweet orange, orange (United States, Eng- 

 lish) ; orange douce (French) ; sinaasappels 

 (Dutch AVest Indies). 



The scientifiic name and apparently also the 

 Puerto Rican common name refer to the country 

 of origin. Formerly known as Citrus aurantium 

 L., a name now restricted to the sour orange. 



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