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BOTANICAL GAZETTE 



[NOVEMBER 



exact effect of acids and bases upon the seed coats and embryos of 

 these seeds, as well as to determine in detail various other points 

 connected v^ith this problem. 



I wish to emphasize again, as I have done already in the paper 

 citedj the fact that delayed germination or failure to germinate is 

 more generally due to seed-coat effects (limiting or entirely excluding 

 water or oxygen supply) tKan to embryo characters, as has generally 

 been assumed. On the other hand, in the same paper, I have shown 

 that the failure of the seeds of hawthorns to grow under ordinary 

 germinative conditions is due to embryo characters, and I have further 

 stated that other seeds probably belong to this category. If seed 

 coats play such an important part in failure to germinate, it is probable 

 that spore coats act similarly in many cases. This hypothesis is now 

 being tested. 



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The University of CmcAGo 



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