THE FLOWER 143 



beginning of September. Some groups of wheat are intermediate between 

 these in their ripening period. 



There is a close correlation between the point at which the first flowers 

 open on an ear of wheat and the region in which the heaviest and largest 

 grains are found. The point differs a little with the race and form of 

 wheat. 



In T. vulgare the heaviest spikelets and grains occur in the middle 

 third of the ear, in winter wheats not far from the union of the middle 

 and lower third, in spring wheats slightly higher and nearer the middle 

 of the ear. 



The average 100- grain weight increases up to the point where the 

 heaviest grains are found, and decreases upwards to the tip. 



The average weight of the grain is higher in the lower than in the upper 

 half. 



In spikelets with more than three grains the second grain is generally 

 the heaviest, and the third and fourth lighter than the first. 



