Newcombe, Sensitive Life of Äsparagus plumosus. 29 



The tips of 3 of these 14 seedlings, for a length of about 

 3 mm, were declined at a smaller angle than the part lower down 

 when the experiment ended; but in the rest of the plants, the tip 

 continued at the same declination as the part below. 



These preparations were continued for 7 weeks after the 

 shoots began to appear above ground, for 34 days after the first 

 seedling took its final diageotropic position, and 28 days after the 

 last seedling took its final diageotropic position. These shoots 

 have stopped growing; there is no indication of a resumption of 

 the vertical position. 



C. Behavior of twining Shoots. 



A description of the appearance and behavior of a normal 

 twining shoot is given under the "Introduction" to this paper. 



Several shoots growing in free earth in a bed in a green- 

 house were chosen for experiment; all showed that they were, in 

 ordinary conditions, destined to climb. They were tested for their 

 behavior in daikness. These shoots were covered with sheetiron 

 or cardboard cylinders 20 cm in diameter and of various hights. 



1) The first shoot selected was 4 mm diameter at the ground, 

 and 27.5 cm in night. It was orthotropic and bore no appendages 

 except the nodal scales. Five days after exclusion of the light, 

 the shoot had reached a hight of 39 cm, and its tip diverged some 

 45° from the narrow bamboo stake stuck into the ground and 

 rising in the axis of the cylinder. It showed no evidence of 

 twining. The tip continued to rise in the same direction for 3 

 days more when it arched over, forming an arc of more than a 

 semi-circle. Such a form of tip as this is taken in the normally 

 growing plant as evidence of twining; but this tip did not twine. 

 For two days more this shoot was watched, and then it died from 

 over-heating in the cylinder unprotected from direct sunlight. The 

 shoot had reached a hight of 41.5 cm but had not twined about 

 the stake. It is probable that, had it been growing in the light, 

 it would have twined for the last 2 of the 10 days it was under 

 experiment. 



In subsequent experiments like the foregoing the covering 

 cylinders were wrapped with several layers of white paper, air 

 Spaces being left between the layers. The removable caps, too, 

 covering the upper ends of the cylinders were similarly protected 

 from the sun. and there was no farther trouble from over-heating. 

 The interior of the cylinders was thus kept cooler than the outside 

 air in the hottest part of the day. This study was made thru the 

 month of August. 



2) A second shoot 35 cm in length, 4 mm diameter at the 

 ground, was covered by a cylinder. Its tip at the time of covering 

 had an S-shape curve 8 cm long. The shoot was tied to a bamboo 

 stake about 7 mm in diameter. After 2 days under cover, the 

 tip became vertical. On the 5th day in the dark, the shoot had 

 grown to a length of 58.5 cm, and its tip was beut in an arc of 



