286 Schively — Contributions to the Life History of 



develops, this tendency becomes manifest. When the 

 ground is reached the tip does not seem to penetrate the 

 soil, but growth takes place and the shoot may extend along 

 the surface for some distance. Many of these runners are 

 quite leafy ; others are devoid of those organs, and show 

 stipules only. From the axils of the stipules grow numer- 

 ous branches of varying length which exhibit geotropisni 

 in beautifully curved tips. 



The extremity of the runner is often turned upward in 

 the most curious manner. In order to ascertain if these 

 runners possessed any apogeotropic tendencies, many of 

 them were given an opportunity to twine. A support was 

 placed for them, they were even assisted by being artificially 

 twined around the stick and then tied to it. In all cases 

 they persistently refused to twine, gradually turned so that 

 the tip inclined downward, and as growth continued they 

 finally reached the soil and behaved as previously described. 



Experiments, made upon the runners when about four 

 inches long, consisted in carefully cutting a sixteenth of an 

 inch, and also an eighth from each apex. The shoots were 

 then supported and inclined upward. In the course of two 

 days, they had grown an inch and showed a decided geo- 

 tropic curve. 



It has been noticed that these runners from the simple 

 leaves appear to be negatively heliotropic. No special 

 experiments have been made which positively prove that 

 this characteristic is stronger than the geotropic one. These 

 axillary runners and their branches continue their growth, 

 finding now a crevice, now a space under a flower-pot — 

 both of which are suitable places for the maturing of ter- 

 restrial fruits. In the green-house, the plants were placed 

 upon a shelf about a yard in width, raised several feet from 

 the floor. Many runners from the plants finally extended 

 across the shelf either directly or diagonally, and continued 

 their growth in the dark space below, many of them 

 maturing fruit. 



In the woods some of the best developed and most fruit- 



