• > ' 

 •ill 



GREEN MANURES AND MANURING 

 IN THE TROPICS. 



CHAPTER I. 

 GENERAL REMARKS. 



The family of the Leguminosce, which numbers not less 

 than 7,000 species distributed over every portion of the 

 terrestrial globe, contains, according to Van Tieghem, 

 430 genera. It includes herbs, shrubs (large and small), and 

 trees of very varying aspect, some species climbing by means 

 of foliar tendrils, e.g., peas, &c. 



The Leguminosai are dialypetalous, dicotyledonous 

 plants, in which the essential character is that the pistil 

 (female organ) is almost invariably formed of a single free 

 carpel. The fruit which results from the fertilization of this 

 carpel is usually a pod {legumen) or legume, and to this the 

 familv owes its name. 



The seeds contain an albuminous substance, " legumin," 

 which is of great importance from a technical point of view. 

 It is certain that owing to its wealth of nitrogen it plays 

 the chief part in the nutritive value of those plants which 

 contain it. Legumin in its ground composition closely 

 resembles other proteid principles contained in plants, but 

 the percentage of nitrogen present is higher. 



The proportion of this body present, in fact, is i8'5 per 

 cent., whereas in albumen and casein the proportion reached 

 is only 16 per cent. 



The Leguminosas are generally divided into three great 

 sub-families : Csesalpine^e, Mimose^, and Papilionaceae. 



I 



