THE INFLUENCE OF GRAVITY 



87 



The lower drawing in Fig. 64 gives the influence of a pair of 

 apical leaves on the formation of roots in a stem which was sus- 

 pended horizontally. Both the upper and lower stems were in 

 the same aquarium and both experiments were carried out simul- 



FiG. 65. — The root formation on the lower side is greater when the mass of 

 apical leaf is greater. May 4 to June 5, 1923. 



taneously (Nov. 18 to Dec. 13, 1923). At and near the base the 

 lower stem (with two leaves at the apex) forms roots on the upper 

 side as well as on the lower. In nodes 1, 2, and 3, however, and 



