VIII spring and its Studies 159 



abnormality such as the fusion of two scales in a fir-cone 

 have upon the spirals ? and so on. Much new light upon 

 morphology used to be hoped for from this study, notably 

 by Alexander Braun of Berlin, half a century ago ; and in 

 our own day the late Professor Dickson has been its most 

 elegant and subtle expositor,^ as Schwendener its most 

 productive student ; it has, however, for most botanists a 

 diminished interest, although we may still hope it holds 

 some floral secrets. 



More important, however, from our present point of 

 view, is the use of this spiral. For most botanists this used 

 to be explained simply as keeping each leaf out of the light 

 of its predecessor (or out of the shadow of its successor, if 

 we prefer to put it so) ; Airy, however, in an interesting 

 paper suggested by Darwin, inclines to interpret it 

 primarily as an adaptation to more perfect bud-packing, as 

 above indicated. Its deeper explanation of course lies in 

 some spiral growth-rhythm which we do not as yet clearly 

 understand. 



From seeds and their germination, from buds and their 

 unfolding, we naturally pass to the life of the adult plant. 

 How is that life sustained from day to day ? The seed had 

 a store of food within itself, and the growth of the young 

 plant is for a time comparable to that of the embryo chick 

 within the ^%%. The store of food within the grain of wheat 

 is analogous to the yolk of the ^g%. But after that is 

 exhausted, how is life sustained t We have already seen 

 that a plant — in some ways so like a sleeping animal — often 

 wakes up in movement, and although the movements are 

 not often so conspicuous as in the climbers, the facts that 

 plants do always move a little, that they force their way 

 into the ground and raise themselves into the air, that, in 



1 The student may with advantage read his chapter on Phyllotaxis 

 in Balfour's Elements of Botany, 



