3o8 BOTANY AND PHARAIACOGXOSY. 



the sub-species sinensis, or it may be a hybrid of lemon and orange. 

 The Navel Orange is a sweet orange in which an additional com- 

 pound ovary is developed within the fruit. 



Lemon and lime fruits are derived from sub-species of Citrus 

 nicdica, which are mostly shrubs with simple, petiolate leaves, 

 reddish twigs and flowers, and more or less ellipsoidal fruits. 

 Lemons are derived from the sub-species Linwnuni. The rind of 

 the fruit yields the oil of lemon, which consists of limonene, 

 citral, etc. Most of the commercial article comes from Sicily and 

 Calabria. Lime fruits or limes are derived from the sub-species 

 acida, a shrub cultivated in the West Indies and Florida. The 

 Citron fruit, the rind of which is used in the making of preserves 

 and confections, is derived from the sub-species genuina. The 

 fruit is large and lemon-like but with a thick rind, the plant being 

 cultivated to some extent in Florida and California. 



The KuMQUAT Orange is obtained from Citrus japonica, a 

 thornless tree with spreading dwarf habit extensively cultivated 

 in China and Japan and very hardy even in Northern Florida. The 

 fruit is round or oblong, from 3 to 5 cm. long and 2 to 3 cm. in 

 diameter, and of an orange-yellow color; the rind is sweet while 

 the pulp is acid, and usually free from seeds, although from 

 I to 4 slightly beaked seeds may be present. 



The inner white portion of the rind of the Citrus fruits con- 

 tains a crystalline, tasteless glucoside known as hesperidin. Those 

 which are bitter contain in addition several bitter glucosides, 

 namely, aurantiamarin and naringin. (See Aurantii Amari Cor- 

 tex, p. 592, and Aurantii Dulcis Cortex, p. 591.) 



Volatile oils are also found in other members of the Rutacese. 

 The garden rue (Rnta graveolens) , the leaves of which are used 

 in medicine, contains a volatile oil consisting of several ketones. 

 It also contains a glucoside known as rutin which resembles the 

 barosmin of buchu ; and quercetin, which is said to be derived from 

 rutin. The Hop tree {Ptclea trifoliata) of Eastern North Amer- 

 ica contains besides a volatile oil, a resin and an alkaloid. The 

 volatile oil of pepper-moor {licinthoxyhiui pipcrifuin) of China 

 and Japan is known as Japanese oil of pepper. 



Angustura bark obtained from Cnsparia trifoliata or C. 

 ofUcinalis, plants growing in the region of the Orinoco River, con- 



