398 



ZSSSONS WITH PLANTS 



We shall expect to find that most kinds of twin- 

 ing plants coil in only one direction. 



501(1. Plants which eoil with the sun, or from the observer's 

 right to left, are known as sinistrorse or eutropic ; those which coil 





Fig. 418. 



Tendril 

 of cucumber. 



against the sun, or left to right, are dextrorse or antitropic. The lat- 

 ter direction is the more common. 



502. Let the pupil watch the free end of a 

 twiner, — as on a young plant which has not yet 

 found a support, or a long tip projecting above* 

 a support — and take note of the position or di- 

 rection of the tip at different times of the day. 

 He will find that the tip revolves in a plane, as 

 if seeking a support. 



503. The cucumber climbs by means of ten- 

 drils (Fig. 418). Notice that the tendril is hooked, 

 in readiness to catch a support. Does the point 

 of the tendril revolve? Watch it closely; or draw 



