The Natural System of Botany. 275 



occupied by the fleshy cotyledons, without any separate albu- 

 men ; a character which is invariable, and which shows the 

 or der to be a natural one. These plants are very generally 

 diffused over the whole world, Papilionaceae being found in 

 almost all countries from the tropics to high northern latitudes, 

 and Mimoseae flourishing principally near the equator. The 

 number of known species amounts nearly to four thousand. 



u A full account of the useful plants and products of this 

 l ar oe order," says Dr. Gray, " would require a separate vol- 

 ume- Many, such . as Clover, Lucerne, &c, are extensively 

 cultivated for fodder ; Peas and Beans for pulse. The roots 

 f the Liquorice, (Glycirrhiza glabra of Southern Europe,) 

 abound in a sweet mucilaginous juice, from which the pectoral 

 extract of this name is prepared. The sweet pulp of the pods 

 ofCeratonia Siliqua (Carob-tree of the South of Europe, &c.,) 

 of the Honey-Locust (Gleditschia,) &c. is likewise eaten. The 

 laxative pulp of Cathartocarpus Fistula, and of the Tamarind, 

 is welt known. A peculiar volatile principle (called coumarin) 

 gives its fragrance to the well known Tonka-bean, and the 

 Melilotus, or Sweet Clover ; the flowers and seeds of which 

 are employed to give the peculiar odor to Gruyere or Scheip- 

 zeiger cheese. 



Astringents and tonics are also yielded by this order : such 

 as the African Pterocarpus erinaceus, the hardened red juice 

 of which is Gum Kino; that of P. Draco, of Carthagena, &c, 

 is Dragon's Blood. The bark of most Acacias and Mimosas 

 contains a very large quantity of tannin, and is likely to prove 

 of great importance in tanning. The valuable astringent 

 called Catechu is obtained by boiling and evaporating the heart- 

 wood of the Indian Acacia Catechu. Leguminosae yield the 

 most important coloring matters ; such as the Brazil-wood, 

 the Log-wood of Campeachy, (the peculiar coloring matter of 

 which is called Hcematin;) and the Red Sandal-wood of Cey- 

 lon. Most important of all is Indigo, which is prepared from 

 the fermented juice of the Indigofera tinctoria, a native of In- 

 dia, and also from I. cerulea, and other species of the genus. 

 To the same order we are indebted for valuable resins and 

 balsams ; such as the Mexican Copal, Balsam of Copaiva, of 

 the West Indies, the bitter and fragrant Balsam of Peru, and 



