16 Newcombe, Sensitive Life of Asparagus plumosus. 
experiments. Moreover, the main axis and the larger branches 
are positively heliotropic after both of these bave taken tbe hori¬ 
zontal position. as has been seen many times in one-sided illumination. 
The lateral branches of all Orders seem to be from the be- 
ginning of their nnfolding diageotropic. They do not begin to 
unfold tili the main axis is near the end of its growth, and they 
have never been seen to assume the vertical position even tem- 
porarily. Since the lateral branches of all Orders before they start 
nnfolding lie appressed and parallel with the axis that bears them, 
and since, in the non-twining shoots, the main axis goes to the 
horizontal position before the lateral branches begin. to unfold, it 
follows that these horizontal branches are already in the horizontal 
Position when they begin unfolding. The shifting of position by 
these branches by which they come, all except the needles, to 
extend nearly at right angles to the respective axes which bear 
them, is therefore not due to diageotropic respose, but must come 
from internal Stimulation which causes each nember, in the language 
of Science, to assume its “proper angle“. The needles, whether 
borne on main axis or a branch of any Order, spread out in a 
horizontal layer like the spokes of a wheel, often filling a complete 
circle, but more often confining themselves to a semicircle. It is 
evident that the diageotropism of all of the horizontal members 
determines their horizontal position, but internal Stimulation de- 
termines the position the branches shall occupy in this horizontal 
plane with respect to one another and to the main axis. So strong 
is this respanse to internal Stimulation that a shoot which has 
taken the horizontal position and is placed parallel to a window 
with one-sided illumination will unfold its branches to the right 
and left of the main axis almost unaffected by the direction of 
light. That is to say, if we imagine a vertical plane to pass thru 
the axis of the horizontal shoot subjected to one-sided illumination, 
so that one side of the vertical plane is shaded and the other 
illuminated, we might expect that an unfolding branch which has 
its origin, say only 10° to the shaded side of the vertical plane, 
would bend across the vertical and place itself on the illuminated 
side. This result, however, does not follow in the experiment, 
but the branch Swings out on the shaded side. 
As pointed out by Miss Conover 1 ), the diageotropic shoots 
when still in a plastic condition make no effort to reverse* when 
the plant isinverted; nor does main axis or brances twist tliru an 
angle of 90° if the plane of the flanks of the horizontal members 
is revolved thru 90° about the horizontal axis. This result can 
mean nothing less than that the diageotropic members are radial 
and not dorsiventral as far as behavior is concerned. Structurally 
also, there is no evidence of dorsiventrality. 
A young orthotropic shoot, revolved on the klinostat tili 
grown to maturity, retains its orthotropic habit and retains also 
l ) Conover, Behavior of Asparagus plumosus howard Gravitation and 
Light. (Plant World. XVI. 1913.) 
