Newcombe, Sensitive Life of Asparagus plumostis. 25 



internodes, shoots having been raised in the dark with 5 to 7 

 times as many internodes as they would have had in the light. 

 To this phenomenon should now be added another, viz. the absence 

 of branches, not including needles. on the eliotated main axis. 

 Among several scores of shoots raised in the dark, 90% have 

 shown not a Single branch. And those giving rise to branches 

 have produced in most cases but one on an axis, never more than 4. 

 Except for the production of a few needles, the unfolding of branches 

 has never gone farther than the primary, save in 3 instances in 

 which the primary branches died at the tip and subsequently gave 

 rise to secondary. These primary and secondary branches produced 

 in the dark show no disposition to take the horizontal position as 

 they do in the light; rather, they nutate, as do the main axes, 

 between the vertical and the horizontal position, and in my ex- 

 periments have often assumed the vertical position for periods of 

 nours and days. 



A little more nttmerous than the primary branches on shoots 

 raised in the dark are the Clusters of needles, as already mentioned 

 when discussing the relations of growth toward light. These needles 

 in the light spread out in a horizontal plane, but on etiolated plants 

 they are stunted and grow out with a brush-like arrangement, as 

 radii of a hemisphere, apparently uncontrolled by gravitation, but 

 oriented by the position of the parent shoot and their relation to 

 one another. 



VI. Development of Diageotropism on Removal 

 of Etiolated Shoots to Light. 



The etiolated shoots of Asparagtts preserve their sensitiveness 

 toward gravitation and light. In several instances, as already 

 stated in this paper, these etiolated shoots have been tested with 

 one-sided Illumination, and found to make positive heliotropic curves 

 within an hour. 



These shoots retain their sensitiveness to gravitation also. 

 A shoot that is vertical in the dark quickly bends bends back to 

 the vertical when displaced. This was to be expected; but it is 

 somewhat remarkable that the divergences which these etiolated, 

 nutating shoots make with the vertical are also closely consequent 

 on the change in response to gravitation. A shoot may be ne- 

 gatively geotropic today, plagiogeotropic tomorrow, and again ne- 

 gatively geotropic on the following day. Sixteen shoots connned 

 in darkness from 1 to 6 months, and having various positions with 

 relation to the direction of gravitation from 0° to 90°, were dis- 

 placed from these positions. . Soine of them returned within 24 

 hours to their former directions, and the others left their new 

 positions for directions more nearly coinciding with their former. 



It is of interest to learn how these etiolated shoots which 

 have never been exposed to light and have never developed a 

 fixed diageotropic position will behave themselves toward gravitation 

 when exposed to ligbt. There have been in my experiments 13 



