HABIT OF GROWTH IS I'LANTS 323 



In pleasing contrast to this j^hasc of vegetable 

 growth is the habit which indicates to us something 

 of mutual help and co-operation. In the CotuposiUe 

 we find many instances of a habit of growth that 

 bears distinctl)' upon this "hclp-one-another" mode 

 of life. A common daisy will serve as a type- 

 flower of this kind. The little head is a colon)- of 

 flowers, but so close is the association of its indi- 

 vidual florets that it is usual to regard it as one 

 flower rather than a distinct inflorescence composed 

 of numerous separate and distinct flowers. 



In order to understand the mutualism displayed 

 by this little flower, we must remember that it is 

 an insect-fertilised blossom, and, therefore, insects 

 must be attracted to it. If we carefully dissect a 

 flower-head we shall find first a ring of strap-shaped 

 flowers on the outside, constituting the ray florets 

 — these are imperfect ;■ but placed side by side on 

 the outer edge they become conspicuous ; then we 

 find in the centre of the flower-head a number of 

 tiny yellow flowers, each one containing stamens 

 and pistils. What wee things they are, and if they 

 were developed singly how inconspicuous they 

 ' Barren. 



