54 



THE VEGETATIVE SHOOT 



many of which receive special names; the most familiar are 

 mentioned below : 



i. Above ground. 



{a) In the wild pear, wild plum, hawthorn, sloe, and buckthorn, 

 some of the branches end in hard, sharp points, termed thorns 

 or spines. That they are modified shoots is seen from the fact 

 that they arise in the axils of- leaves, and also themselves bear 

 leaves and lateral buds in some instances. 



Fig, 21, — Runner of Creeping Crowfoot {Ranu7tcnltis repens L.). 

 ;- Adventitious roots; s internodes, 



(b) A runner or stolon is a shoot which extends horizontally over 

 the surface of the ground. Its internodes are long, and from its 

 nodes adventitious roots are produced, and grow into the soil 

 (Fig. 2i). The buds present on the runner then become 

 fixed to the ground, and, developing into upright shoots, form 

 separate plants as soon as the internodes at j die away or are 

 severed. 



Strawberry runners and those of creeping crowfoot are good 

 examples. 



