40 Newcombe, Senuitive Life of Asparagus pluniosiis. 



Eowever, tho the shoot at its earliest origin predestined to be a 

 short non-twiner with horizontal tip, and the shoot predestined at 

 its origin to be a twiner lnay be the samelength, meters Ion«;-, in 

 the dark, niay look alike and bchave aliko, the one is still in its 

 inner capacity a non-twiner and the other a twiner, as subsequent 

 exposure to the light demonstrates. 



Lateral buds fail to unfold in the dark, and this may be 

 regarded as an exemplification of the principle of conservation. 

 The failure of the needles to attain their fall size in the dark may 

 be referred to the same class of phenomena as the stunted growth 

 of leaves in the dark, since the needles are the assiinilatingorgaiis. 



The biological significance of the horizontal bend of the upper 

 third to a half of the non-twining normal shoots is not easy to 

 perceive. If one were acquainted with the native environment of 

 the plant the task might be easier. None of the benefits assigned 

 to similar behavior on the part of Hedera helix, Tropaeolum, Cu- 

 curbita, Gleclionm, Vinco and others will answer for Asparagus, 

 for the reason that immediately on taking the horizontal position, 

 Asparagus ceases to grow in length. If one observes a potted 

 plant with 6 to 12 non-twining shoots he sees that the horizontal 

 portions of these shoots are in stories, one above another, the 

 oldest below and the last formed the uppermost. The shoots in- 

 terfere very little with one another, their arrangement in stories 

 leaving horizontal Spaces between the stories of fronds. This ar- 

 rangement also can hardly cause sufficient shade to reduce the 

 carbon-assimilation of the lowest story of shoots, for the fineness 

 of the members of the branching System and their distance apart 

 allow abundant light to penetrate to all shoots. But if the shoots 

 grew erect, there would probably also be sufficient light tho the 

 branches of the shoots would be crowded more closely together. 

 If the plants grew closely together in beds, it would seem as tho 

 the horizontal position would cause as much crowding as the ver- 

 tical. Inasmuch as in nature we may suppose the direction of the 

 plane of the diageotropic curve to be usually determined by the 

 positive heliotropism of the shoot, it might follow that the shoot 

 would receive more light in the horizontal position, because of 

 shading from above, than tho it grew erect. 



Summary. 



1. In form and behavior, Asparagus plumosus var. nanus, 

 possesses 3 kinds of aerial shoots: 1) Seedling shoots which grow 

 to a length of 10 cm to 15 cm, bend their terminal 3 cm to 5 cm 

 into a plagiogeotropic position, while the branches not needles 

 show a weak form of plagiogeotropism, and the needles are almost 

 indifferent to gravitation; 2) non-twining shoots from rhizomes which 

 attain a length of 10 cm to 60 cm, bend the upper one-third or 

 one-half of the shoot to the horizontal, while branches of all Orders 



