THE PLANT 23 



story at the stage when the seedling is well established, 

 with several leaves, and a field of them is beginning to 

 bear a rough resemblance to a crop of potatoes. 



If the seedlings before this stage have been stunted 



through any cause, such as imprisonment under clods 



or in stiff soil, through the bite of a 



prowling caterpillar or the rotting action 



of fungi, by heat or by water shortage, they will be 



smaller than their neighbours, take longer to open their 



first flower, and will therefore other things being equal 



yield less cotton, simply because they have less time in 



which to open and ripen their flowers. 



Similarly, seed which is sown too late will yield a 



smaller crop for the same reason, though the plants may 



grow better than their early-sown neigh- 



Sowmg- k ourgj stage f or s tage. It does not follow, 

 JLim6. 



however, that sowing very early is of any 



advantage; it may be pernicious, and in Egypt there 

 is a Critical So wing -Date in each district, which varies 

 only a few days from year to year. Sowings made 

 moderately early before that date all do equally well, 

 while sowings made afterwards are proportionately later 

 in flowering (Fig. 2). It is obviously best to sow on the 

 critical date itself, since the chances of a cold spell are 

 less as the summer approaches. 



That this should be the case is obvious on a little re- 

 flection. Cotton is usually sown when the weather is 

 getting warmer (when the reverse, as in the Sudan, the 

 same arguments apply), and there are two ends to the 

 plant, of which the root is equally important with the 



