iQig] ROSE— AFTER-RIPENING AND GERMINATION 307 



will result in heating. The seeds should be left in the acid for 

 approximately 2 hours. 



In order to obtain uniform results it is advisable to use a large 

 excess of acid and to prevent the seeds from gathering in clumps or 

 ■layers. Frequent stirring is essential. By rubbing a few of the 

 seeds in the palm of the hand from time to time it is possible to 

 determine when the entire endocarp on a majority of the seeds has 

 been carbonized. When this point is reached the acid should be 

 drained away and the seeds thrown into an excess of cold water. 

 It is advisable to change the water frequently or to put the seeds 

 in running water, where they should be left for at least 15 minutes. 

 When they are removed from the water they should be treated 

 with an excess of a 5 per cent solution of sodium bicarbonate until 

 bubbles cease to rise, after which they may be washed in running 

 water for 15 minutes. 



In order to remove the carbonized endocarp the seeds may be 

 placed on filter paper and rubbed under the fingers. It is impossible 

 to remove the endocarp if it has been allowed to become dry follow- 

 ing the last washing. 



The writer is indebted to Dr. William Crocker and Dr. 

 Sophia H. Eckerson for many helpful criticisms and suggestions 

 during the progress of the work. 



Missouri State Fruit Experiment Station 

 Mountain Grove, Mo. 



LITERATURE CITED 



1. Appleman, C. O., Some observations on catalase. BoT. Gaz. 50: 182-192. 

 1910. 



2. BoLLEY, H. L., The agricultural value of hard coats in alfalfa and clover 

 seed. Paper read before the Association of Seed Analysts, 1910. 



3. Bruyning, J. F. On the use of hot water for forcing germination in hard 

 coated seeds. Jour. Landw. 41:86. 1896. 



4. BuNZELL H. H., A simplified and inexpensive oxidase apparatus. Jour. 

 Biol. Chem. 17:409-411. 1914. 



5. Crocker, W., Mechanics of dormancy. Amer. Jour. Bot. 3:99-120. 1916. 



6. Crocker, W., and D.avis, W. E., Delayed germination in the seeds of 

 Alisma Plantago. Bot. Gaz. 58: 285-321. 1914. 



7. Davis, W. E., and Rose, R. C, The effects of external conditions upon the 

 after-ripening of the seeds of Crataegus mollis. Box. Gaz. 54:49-62. 191 2. 



