112 TALKS AFIELD. 



node may be likened to a bow which has its 

 convex and its concave sides directed suc- 

 cessively to every point of the compass. It 

 is not to be understood that this elongation or 

 growth is uniform on all sides of the stem ; 

 in fact, it is commonly not so, and the shoots 

 oftener revolve in ellipses or irregular paths 

 than in true circles. One ordinarily asso- 

 ciates the revolving with a twisting of the 

 stem, but no such twisting takes place to 

 any extent. There are three reasons why 

 twisting of the stem does not cause the mo- 

 tion : the young shoot begins its revolution 

 before any twisting is to be observed ; few 

 stems twist more than three times around 

 while they make thirty or more revolutions ; 

 many plants revolve which never twist. 



Tendril -Climbers. — The tendril-climbers 

 exhibit more remarkable peculiarities than 

 the twiners. Before us is a picture (Fig. 

 83) of the "wild cucumber " or Echinocystis 

 of our glades, and which is now generally 

 grown over windows and bushes. Opposite 

 the three-lobed leaf is a three-parted tendril. 

 A critical observation of the growing plant 

 would discover a revolution of the two upper 

 internodes the same as in twiners, only of less 

 extent. The tendrils also revolve, sweeping 



