310 THOPICAL AGRICULTURE 



cattle. For the latter purpose it is superior to the jack bean, 

 which often possesses a bitter flavor. 



Crotalaria, under various specific forms, occurs everywhere 

 in the Tropics. One of these species is sunn hemp (C 

 jttncea), which is discussed under fiber plants but is also much 

 used as a cover crop. This is a slender, erect species, with 

 conspicuous yellow flowers. One of the most important forms 

 of Crotalaria for use as a green manure in Hawaii is C. sal-, 

 tiana, which has in recent years given a good account of 

 itself for this purpose. This form of Crotalaria is unusually 

 hardy. It thrives either in wet or dry districts. It will make 

 a fairly good crop under a rainfall of 20 inches and thrives 

 abundantly under a rainfall of 200 inches. The seed will 

 germinate promptly without attention after scattering broad- 

 cast upon the soil. This Crotalaria is not useful for feed but 

 is an exceptionally good green manuring crop. It is not at- 

 tacked by insects, except the blue butterfly, which merely 

 reduces the number of pods. The seed of the plant can be 

 readily obtained by offering children 10 cents a pound for it. 

 This species of Crotalaria has been recently used with pro- 

 nounced success as a green manuring crop in Hawaii and 

 elsewhere. 



The kudzu bean {Pueraria thunbergiana) of Japan and 

 China is quite hardy outside of the Tropics. It is a perennial 

 legume with large starchy roots. The plants grow only a 

 few feet during the first season, but may reach a length of 

 40 to 75 feet during the second year. It is propagated in 

 Florida by cuttings or seed and is used as a cattle pasture 

 and as an arbor vine. Moreover, in Japan a fine grade of 

 starch is extracted from the roots for special use in con- 

 fectionery. Kudzu bean yields a heavy crop of hay which 

 contains about 17 per cent, of protein and 30 per cent, of 

 carbohydrates. 



The adzuki bean {Phaseolus angularis) of southeastern 

 Asia is widely grown for human food in China, Japan, and 



