New com be. Sensitive Life of Asparagus phimosus. 15 



These nodal scales on a stout shoot attain a considerable 

 size — a centimeter or niore in length — are closely appressed 

 to the bearing axis, and are produced below into a stout divergent 

 spine 3 to 7 mm in length. This rigid spine must certainly be 

 of use in climbing in the plant's native habitat. 



Twining is, in a certain sense, predestined. A shoot Coming 

 thru the ground with a diameter of more than 2 mm is almost 

 certain to become a twiner. I have not seen shoots more than 

 4 mm in diameter. Should a twiner find no support to enable it 

 to rise, it wanders about over the earth, or plant growth, as do 

 other climbing plants, its cord-like stem of 2 or 3 meters length 

 wholly destitute of any appendage except for the spinous nodal 

 scales. 



This Asparagus twines either clockwise or counterclockwise. 

 I have seen a shoot Start twining and make a complete turn about 

 the supporting cord, then unwind itself and twine in the opposite 

 direction for its final course. 



Experiinental. 



A. Non-twining shoots from rhizomes. 



I. Geotropic Relations. 



In the paper by Miss Conover 1 ), already referred to, it has 

 been shown that young shoots of this Asparagus are orthotropic 

 and negatively geotropic. The same Author has shown also that 

 the horizontal position assumed by the shoot when nearing its 

 maturity is due to a reversal of response to gravitation, the shoot 

 changing its negative geotropism to diageotropism. 



This diageotropism pertains not only to the main axis but 

 to all the branches also. As the branches of the first order start 

 unfolding. they lie close to and parallel with the main axis. As 

 they become a centimeter or more in length they swing thru an 

 are of approximately 90°, sometimes 180°, and always come to 

 rest in the horizotal position. That the assumption of this position 

 is not a heliotropic response can be shown by a klinostat experi- 

 ment: Several pots, altogether with 8 developing shoots, have been 

 revolved on the klinostat so as to neutralize gravitation, but not 

 to neutralize light. The main axes and the lateral branches of 

 the first order have shown positive heliotropic responses, but never 

 negative nor transverse heliotropic, tho the revolution was con- 

 tinued tili the plants had reached maturity. YYere the horizontal 

 position of main axis and branches due to the antagonistic working 

 of geotropism and heliotropism, or to transverse heliotropism, we 

 ought to have corresponding heliotropic movements in these klinostat 



') Conover, Behavior of Äspar<nins /i/umosiis toward Gravitation and 

 Light. (Plant World. XVI. 1913.) 



