Newcombe, Sensitive Life of Asparagus plumosus. 15 
These nodal scales on a stout shoot attain a considerable 
size — a centimeter or more in length — are closely appressed 
to the bearing axis, and are produced below into a stont 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. 
Experimental. 
A. Non-twining shoots from rhizomes. 
I. Geotropic Relations. 
In the paper by Miss Conover 1 ), already referred to, it has 
been shown that 3 7 oung 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 
arc 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. Were the horizontal 
Position of main axis and branches due to the antagonistic working 
of geotropism and hcliotropism, or to transverse heliotropism, we 
ought to have corresponding heliotropic movements in these klinostat 
>) Conover, Behavior of Asparagus plumosus towarcl Gravitation and 
Light. (Plant World. XYI. 1913.) 
