338 



BOTANICAL GAZETTE 



[XOVEMBER 



contain only 17-20 per cent of the total, and most of it exists as 

 organic nitrogen. The portion representing inorganic nitrogen is 

 the nitrate nitrogen, which is relatively small. Calculated as 

 nitrates (NO3), the seeds contain o. 20 per cent, and this is equiva- 

 lent to 1.80 per cent of the total nitrogen (tables VII and VIII). 

 The lipin nitrogen is very small, only 0.027 per cent in A. blitoides 

 and 0.032 per cent in A. retroflexus. These represent i.io and 

 1. 3 1 per cent respectively of the total nitrogen content in these 

 two seeds. In general a high percentage of insoluble phosphorus 

 is accompanied by a high percentage of insoluble nitrogen, and a 

 low percentage of soluble phosphorus by a low percentage of soluble 

 nitrogen. 



Carbohydrates. — The polysaccharides are the predominating 

 sugars in these seeds. A. retroflexus seeds contain 46 per cent 

 and A. blitoides 47.75 per cent polysaccharides (on dry weight 



TABLE IX 



' Carbohydrates in seeds (percentage dry weight) 



Material 



Lipin sugars 



Reducing sugars . . . . 



Non-reducing sugars 



Polysaccharides. . . . 



Total 



Non-reducing 



Polysaccharides. . . . 

 Total 



basis). If these sugars are calculated on the dry basis of the total 

 sugars, the polysaccharides represent 97.60 and 98.60 per cent 

 respectively in these two species. A striking contrast is seen on 

 comparing the amount of polysaccharides in the green plant organs 

 (figs. 6-8), which vary only slightly throughout the growing period, 

 with that found in the seeds. In the growing period the highest 

 percentage of polysaccharides was only 14.85, while that of the 

 seeds was 47. In addition to this noticeable contrast, the soluble 



