SHOOTS 77 
have been given to every kind of variation, so that their 
study is often not much more than learning the definitions 
of names. However, if we seek to discover the life-rela- 
tions of flowers we find that they may be stated very simply. 
55. Life-relations. The flower is to produce seed. It 
must not only put itself into proper relation to do this, but 
FIG. 69. The rootstock of a rush (Juncus), showing how it advances beneath the 
ground and sends above the surface a succession of branches. The breaking up 
of such a rootstock only results in so many separate individuals. After COWLES. 
there must also be some arrangement for putting the seeds 
into proper conditions for developing new plants. In the 
production of seed it is necessary for the flower to secure a 
transfer of certain yellowish, powdery bodies which it pro- 
duces, known as pollen or pollen-grains, to the organ in 
which the seeds are produced, known as the pistil. This 
transfer is called pollination. One of the important things, 
therefore, in connection with the flower, is for it to put 
