Ill DEVELOPMENT AND ENVIRONMENT 6i 



ever, the main axis had reduced its growth-rate below even 

 that which was possible under these conditions, and the 

 effects of root-asphyxiation are shown by the laterals only, 

 as in the flowering-curve. 



A peculiar confirmation of the interpretation just given 

 as to the influence of the soil-water in July is shown by 

 the growth-curves of families sown at diff"erent times. 

 During the week ending on June 26th, 1911, a depression 

 of the growth-rate was recorded in the oldest family, while 

 the oldest but one showed it in a less marked form. The 

 remaining families were unaffected. When we consider 

 that the earlier the plant is sown, the larger its root-system 

 must be, we see that the drjang-effect of the early plants 

 on the soil surrounding them will be more severe than in 

 the case of the later plants, and hence they will show the 

 soil-water limiting effect at an earlier date. 



The flowering-curve. — As in the case of the growth- 

 curve, we meet with specific differences in the manner of 

 distribution of flower-production in time. The beginning 

 of the curve, as the date of appearance of the first flower, 

 has already been discussed. 



The specific diff"erences in growth-reaction to environ- 

 ment, which we have just discussed, aff'ect the form of this 

 curve also. Thus, owing to the habit of " early growth- 

 cessation " taking place first in the oldest bud, namely, the 

 terminal one, and then progressively in the younger ones, the 

 growth of the flowering branches is checked in the strain 

 of King Uplands by the end of July, and no flowers open 

 during August or September. By the end of August a 

 plant of King appears to be dead, but the flower- 

 ing begins again in October, and a second crop of bolls 

 may be produced from these flowers. The Egyptian 

 Sultani strain already mentioned, with its continuous 

 growth-habit, continues to flower throughout the season, 

 while the usual Egyptian flowering-curve rises to a 

 maximum in the beginning of August, and then descends 



