30 SAGACITY AND MORALITY OF PLANTS. 



The leaves of plants are all arranged on the 

 stems and branches so that each can do its work 

 without interfering with the rest. Their multitu- 

 dinous shapes, also, have distinct reference to their 

 capability of decomposing carbonic acid. The pro- 

 cess of spiral growth {phyllotaxy) gradually pushes 

 out the leaves we see packed away in every leaf-bud, 

 until at the end of the summer a long twig, with leaves 

 arranged along all its length, has developed from 

 it. The places where the leaves have developed are 

 called nodes — the spaces between the leaves are 

 known as inter -nodal spaces. The characteristic 

 foliage of a tree very much depends on the length 

 of the spaces between the leaves. Sometimes we 

 have no spaces at all — the latter are " suppressed." 

 Then we have the rosette arrangement of leaves 

 matting the ground like those of the Daisy, Thistle, 

 Hawkweed, and many others. When the leaves are 

 large, as in the Horse-chestnut, there are few of them 

 composing the spiral ; when the leaves are small 

 they are numerous, as in the Pine and Larch-trees. 

 Usually, the inter-nodal spaces get shorter towards 

 the end of a branch, and sometimes they are 

 almost suppressed there, so that the terminal leaves 

 are arranged like a rosette. This is the case with 

 the Rhododendron and the Poinsettia. In the latter 

 plant the rosette -grouped leaves are of a bright 

 scarlet colour, and so attractive that the flowers are 

 placed there, and no gorgeous petals are required to 



