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HALSTED— POSITION OF SEEDS 



247 



A comparison of the weights of seeds for each pod position in 

 the combined harvests of pods without aborts (table III) with those 

 with aborts (table IV) shows that the former are uniformly lighter, 

 as seen in the following statement : 



Pods without aborts. 

 Pods with aborts 



First harvest 



0.360 gr. 

 0-377 



Second 



harvest 



0.426 gr. 

 0453 



Both harvests 



0-385 gr- 

 0.414 



The pod averages for seed- weights (tables III, IV) show that the 

 seeds of 3-ovuled pods without aborts are heavier than are the seeds 

 (average weights) in the other two types of pods, while among pods 

 with aborts the average seed weight is greatest in 2-ovuled pods. 

 This is shown in the following figures, in which both harvests are 

 combined : 



2-ovuled 



Pods without aborts. 

 Pods with aborts 



0.352 gr. 

 0.440 



3-ovuled 



0.391 gr. 

 0.418 



4-ovuled 



0.333 gr- 

 0.373 



From these averages it is seen that the differences are con- 

 siderable, and it may be assumed that it is due to local environment 

 within the pod. For example, in a 2-ovuled pod the average weight 

 of the seeds is 25 per cent more when one ovule aborts, 6 . 93 per cent 

 in 3-ovuled pods, and 12.01 per cent in 4-o\'nled pods. It is noted 

 that the differences are greatest in the extreme or, as they may be 

 called, exceptional pods. The influence upon the remaining seeds 

 when two or more ovules abort in the larger types of pods cannot 

 be determined from the records. 



Percentages of gains in weight of seeds associated with aborts 

 over the weight of seeds from pods without aborts for each position 

 in the pod are as follows: 



Pod averages 



AU 



7-79 



