Newconibe, Sensitive Life of Asparagtis plumosus. 27 



negative geotropism and positive keliotropism. At a time when 

 branches of the first and second order are well unfolded, if the 

 revolution of the klinostat is stopped at night, 3 or 4 hours suffice 

 to produce upward curves at the tips of the main axis and branches. 

 If the revolution is so carried out that the access of light is not 

 equalized, the tips of the main shoot and branches will bend toward 

 the stronger light. These results are wholly different from what 

 one sees in plants in normal development; for in them main axis 

 and branches are diageotropic as soon as the primary branches 

 begin to unfold. 



It has been shown in the work of Miss Conover, as well 

 as my own, that the diageotropic axis of Asparagus is in a position 

 of equilibrium however it may lie in the horizontal plane; and the 

 same is true of the branches. Why then should this plant not 

 develop diageotropism when revolved on the klinostat? Suppose that 

 the plant is so revolved that its main axis is parallel with the 

 horizontal axis of the klinostat. The main axis is always horizontal, 

 but in spite of this it remains negatively geotropic. And in the 

 same conditions of revolution the branches of the first order might 

 place themselves in the horizontal position during revolution by 

 bending forward or backward, parallel with the main axis. 



Suppose, on the other hand, that the plant is fastened to the 

 horizontal axis of the klinostat with the axis of the plant at right 

 angles to the klinostat axis. In this position, some of the branches 

 of the first order would be always in the horizontal direction if they 

 merely grew out at right angles to the main axis. The main axis 

 might place its tip in the horizontal (diageotropic?) position by 

 merely turning 90° to the right or left of the direction of its older 

 part. The evidence, however, is conclusive that diageotropism is 

 not at all developed during revolution on the klinostat. 



As the development of diageotropism has been detailed above 

 for shoots placed in light after being raised in the dark, so the 

 same process could be followed for shoots developed on the klinostat. 

 But on the klinostat, main axis and branches hasten to their flxed 

 position, while in the dark they make slow progress on their 

 journey. Tims the development of diageotropism in plants raised 

 to füll maturity on the klinostat cannot be demonstrated by changes 

 for which growth furnishes the evidence. The best that can be 

 done is to remove such plants from the klinostat before theyhave 

 wholly completed their growth. This has been done in the case 

 of 2 pots with 5 shoots. The result was for the first one or two 

 days a negatively geotropic ' elevation of the tips of the branches, 

 followed after 3 days by a depression to the horizontal. The tip 

 of the main axis also goes to the horizontal. The older parts of 

 main axis and branches, which have unfolded in multiradial arran- 

 gement, retain this arrangement permanently, giving to the plant 

 a very odd appearance. 



