TWINERS AND CLIMBERS. 



195 



amount of warmth. The twining Polygonum {Poly- 

 gonum convolvulus), however, twines only during the 

 middle of the summer ; in the autumn they will grow 

 vigorously, but without any inclination to climb. 



Fig. 24. — The Twining Polygonum (Polygonum convolvulus). 



Most of the garden beans, of the scarlet runner kind, 

 are excellent twiners, whilst some of the varieties 

 exhibit no tendency to twine. 



The only other point to which we shall allude in 

 O 2 



