no 



THE PEANUT— THE UNPREDICTABLE LEGUME 



ing its development. As stated previously, mature seed have a higher oil 

 content than immature seed. Very immature seed are quite high in free 

 fatty acids (62) which decrease to a low level at maturity. Gallup and 

 Staten (31) report an increase of protein and oil and a decrease of crude 

 fiber and nitrogen-free extract of seed with shells during the last 5-week 

 period of development. 



Analysis (43) of the skin or testa of seed shows it to be high in fiber 

 and ash and to contain appreciable amounts of fat and nitrogenous ma- 

 terials. 



Shells 



The mineral composition of shells is given in table 4. The mineral 

 content of seed is little affected by fertilization, whereas that of the shell 

 (28, 51, 52) has been used as an index of the calcium supply available to 

 the developing fruit. Indications are that at least four factors affect the 

 mineral composition of shells, namely (a) development of seed, (b) 

 nature of the soil colloids, (c) calcium and other nutrients supplied the 

 peanut, and (d) the length of tifne the fruit remains in the soil. Empty or 

 poorly filled shells (28) have a higher nitrogen, potassium and magnesium 

 content than the shells with well-developed seed, while the calcium con- 

 tent of the shell is not consistently affected by seed development. The 

 peanut fruit seems to be able to obtain more calcium (51, 52) from some 

 types of soil colloids than from others with the same degree of calcium 

 saturation. Moreover, the application of calcium to the soil where peanuts 

 are grown increases the calcium content of the hulls (28). Results by 

 Bledsoe and Harris ( 10) indicate that the shell of the fruit absorbs very 

 small amounts of magnesium arid phosphorus from the medium in which 

 it develops but actively absorbs calcium (9) and possibly potassium. The 

 writers have observed also that the potassium content of shells of peanuts 

 which cling to the vines when harvested is much higher than that of shells 

 of peanuts removed ff6m the soil after harvest. 



The approximate organic composition of peanut hulls as compiled 

 from the results of Fraps (30) is given in table 8. Little work has been 



