THE SYCAMORE ''KEY" 



upper example, where each hairy ovary is seen 

 slowly developing into two winged seeds. In Fig. 

 20 (Plate 14) the work is seen completed, and I 

 scarcely need say that in each of these winged 

 seeds there is a little seedling plant, for have we 

 not previously seen one develop from such a seed ? 

 If you need further convincing, you have but to 

 anticipate Nature by carefully cutting open with 

 the point of your penknife the rounded base of a 

 fully-developed seed, and there you will find the 

 little plant carefully packed away, and you may 

 poke it out and unfold its nurse-leaves, as these are 

 quite large enough for you to examine with the 

 unaided eye. 



There now only remains the question : how 

 the seeds should have developed wings to soar 

 upon the wind ? Well, the answer is exceedingly 

 simple. The ovary, to begin with, is flat and 

 divided into two halves, each bearing a thin edge 

 at its upper corner. Now, naturall}', some seeds 

 would, in the early stages of the sycamore's 

 history, occasionally be thinner and flatter at their 

 corners than others, and when the time came for 

 the seeds to fall from the parent tree, these 

 thinnest seeds would get carried farthest by the 

 wind, and would consequently stand the best 

 chance of prospering, and so from these early and 

 accidental examples have been slowly evolved the 

 more efficient forms, until to-day we have the 

 seed, or ^^key," as we know it. 



Finally, how was the graceful whirling flight 

 of the seed acquired ? Well, that, I think, is 



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