26 



BOTANY FOR BEGINNERS 



CHAP. 



of which it fixes itself to walls, trees and shrubs. Cleavers, 



which is a struggling, rough and matted plant found in hedges, 



is another good example of a plant which climbs by means of 



hooks (Fig. 23). 

 Stem -Climbers. When the stem of the hop plant comes 



out of the ground its first 



two or three internodes grow 



up erect. The young inter- 

 nodes which are produced 



from the top of the first- 

 formed portion commence to 



bend slowly and gracefully 



to one side and travel 



steadily round to every point 



of the compass, describing 



a complete circle in the 



direction the minute hand 



of a watch moves over its 



face. Should the twining 



stem of the Hop come in 



contact with a support, the 



part which it strikes is seized FlG - 23--The hooks of the Bramble. 



by the hooks which are well 



developed on the stem. The stem still grows at the apex and 



goes on twining, thus climbing more and more about the 



support. The Bindweed or Convolvulus also climbs by means 



of twining stems, but these 

 climb in the opposite direc- 

 tion to the Hop, i.e., to- 

 wards the left. The stems 

 of the Hop and Honey- 

 suckle turn round from the 

 west through the south 

 towards the east ; this is 

 called twining to the right. 

 The Scarlet Runner and 



W 



FIG. 24. Diagram illustrating how plants 

 twine. The left-hand figure shows how 

 the Honeysuckle twines to the right ; the 



ight-hand figure how the Convolvulus 



wines to the left. 



twines to the 



the Bind-weed turn round 



.from the west through the north towards the east ; this is 

 termed twining to the left (Fig. 24). 

 Plants which Climb with Sensitive Organs. This 



