LEGUMINOS^. 479 



The preceding is the estimate of species in the different sub-orders and 

 tribes, considered in reference to the flora of the globe and the flora 

 of Britain (Bentham and Henslow). The number of known genera 

 at the present day is about 400, including about 6500 species. 



This is a very extensive and a very important natural order. 

 It embraces many valuable medicinal plants, such as those yielding 

 Senna, Gum-arabic, Tragaoanth, Catechu, and Kino ; important 

 dyes, as Indigo and Logwood ; many valuable timber-trees, as Locust- 

 tree and Kosewood ; plants furnishing nutritious food, such as the 

 Bean and Pea, Haricots, Kidney-beans, Lentils, Pigeon-peas, Chick- 

 pea. The properties of the order may be considered in general as 

 wholesome, although it contains some poisonous plants. Lindley, 

 however, says that the order must be considered upon the whole as 

 poisonous, and that the plants used for food are exceptions to the 

 general rule; the injurious juices of the order not being in such 

 instances sufficiently concentrated to prove injurious, being replaced 

 to a considerable extent by either sugar or starch. 



Sub-order Papilionacece. The plants in this section have frequently 

 beautiful showy flowers ; for example, Bohinia, Laburnum, Wistaria, 

 Lupinus, Clianihus, Erythrina (Ooral-flower), Hovea. They are often 

 nutritious. The various kinds of Clover, Beans, Peas, and Pulse 

 belong to it. The common red Clover is Trifoliwm pratense. White 

 or Dutch Clover (T. repens) springs up frequently on ground recently 

 cleared. The Shamrock is generally considered as a species of Trefoil. 

 Various species of Medick and Lucerne (Medicago, fig. 567, p. 313), 

 of Saintfoin (Onobrychis), and MelUot (Melilotus), are cultivated as 

 food for cattle. Several species of Medicago are called Calvary Plants, 

 on account of dark, blood-like spots on their leaflets. Medicago 

 Echinus is one of the symbolic plants of the East. Many are used for 

 their medicinal qualities. Olycyrrhiza glabra. (Liquiritia officinalis) 

 is the plant which yields liquorice-root. This plant is a native of the 

 southern part of Europe, and it has been occasionally cultivated with 

 success in Britain, especially at Pontefract in Yorkshire, and at 

 Mitcham in Surrey. An extract is prepared from the root or under- 

 ground stem by decoction in water, and subsequent inspissation. It 

 owes its sweetness to a peculiar principle called Glycion, or Glycyr- 

 rhizin, which appears also to be present in the root and leaves of other 

 papilionaceous plants, as Glyoyrrhim echinata and glanduUfera, Tri- 

 folium alpinum, and Abrus precatorius. Liquorice is used medicinally 

 as a demulcent. A sweet secretion (a kind of Manna) is produced by 

 Alhagi Maurorum (Camel's-thorn). Astragalus veru.s, creticus, aristatus, 

 gmnmifer, and other species, yield an exudation known by the name 

 of Gum Tragacanth. A. verus seems to be the chief source of the 

 European tragacanth. It is a shrub found in Asia Minor and Persia, 

 and the gum is procured by exudation or incision. Tragacanth forms, 



