RUTACE.E 485 



Hood and Russell have recently pointed out that the ex- 

 traction of sweet orange oil is a commercial possibility in 

 this country, and that waste oranges may be utilized. 



CITRUS NOBILIS (King Orange) 



Description. — The King orange tree is 12 to 20 feet tall, 

 with slender, drooping branches, and thornless, or with small 

 sharp spines; the leaves are small, lanceolate to oval, and the 

 petioles are wingless or very narrowly winged; the flowers 

 occur singly or in small clusters; the petals are white above 

 and below, fleshy and recurved; there are from 18 to 24 

 stamens; the ovary has 9 to 15 locules; the fruit is oblate, 

 orange to reddish in color, its peel loose and easily removed, 

 the pulp sweet or sub-acid, and the juice sacks broad and 

 blunt. 



Varieties. — Citrus nohilis var. deliciosa is the mandarin 

 orange. In this variety are included the tangerine varieties, 

 which have an easily removable skin and segments that come 

 apart readily, also the tangelo which is a hybrid between the 

 tangerine and the Bowen grapefruit. Citrus nobilis var. 

 unshiu is the Satsuma or Unshiu orange. It is a small, 

 spineless, dwarf tree, and very hardy. 



CITRUS GRAinsiS (Grapefruit, Pomelo, Shaddock) 



Description. — This species is a large tree, 20 to 40 feet in 

 height, with slender, flexible spines, if present; the leaves 

 are large, ovate, crenate, broadly rounded at the base, and 

 the petioles are broadly winged and 'articulated; the flowers 

 are borne singly or in clusters of 2 to 20; the petals are white 

 both above and below; there are from 20 to 25 stamens, with 

 large linear anthers; the ovary has from 11 to 14 locules; the 

 fruit is very large, 4 to 6 inches in diameter, globose, oblate 

 or pear-shaped, pale lemon-yellow when ripe, its skin smooth, 



