THE ASH OF PLANTS. 155 



stant decrease, except at the time of ripening, when these 

 relations are reversed. The knots of the stem preserved 

 a pretty uniform ash-content. The unhusked grain at 

 first suffered a diminution, then an increase, and lastly a 

 decrease again. 



Arendt found in the oat-plant fluctuations, not in all 

 respects accordant with those observed by Norton. 

 Areudt obtained the following proportions of ash : 



Here we see that the ash increased in the stem and in 

 each of its several parts after the first examination. The 

 lower leaves exhibited an increase of fixed matters after 

 the first period, while in the upper leaves the ash dimin- 

 ished toward the third period, and thereafter increased. 

 In the ears, and in the entire plant, the ash decreased 

 quite regularly as the plant grew older. Pierre found 

 that the proportion of ash of the colza (Brassica olera- 

 cea) diminished in all parts of the plant (which was 

 examined at five periods), except in the leaves, in which 

 it increased. (Jdhresbericht uber Agriculturchemie, III, 

 p. 122.) The sugar-beet (Bretschneider) and potato 

 (Wolff) exhibit a decrease of the per cent of ash, both in 

 tops and roots. 



In the turnip, examined at four periods, Anderson 

 (Trans. High, and Ag. Soc. , 1859-61, p. 371) found the 

 following per cent of ash in dry matter : 



July 7. Aug.ll. Sept. I. Oct. 5. 



Leaves 7.8 20.6 18 16.2 



Bulbs 17.7 8.7 102 20.9 



In this case, the ash of the leaves increased during 

 about half the period of growth from 7.8 to 20.6, and 



