124 -The Botanical Gazette. [April 
months January—April, and September—December, 1892. 
The observations were extended to include P. Pfordti of tht 
gardeners. The temperature varied between 16 and 35°C 
It is of interest to note that both of these forms exhibited 
marked nutation of the terminal internodes of the stem, site” 
in the species examined by Darwin such was found to be 
case only in P. gractlis.* eo 
This circumnutation of the tendril and the internode bearing 
it begins when both are quite rudimentary(fig. 3). These move 
ments with the individual movements of the yet immaturel 
ternodes below combine to sweep the tendril through a large 
space during its period of greatest activity, thereby greatly 
increasing the probability of coming in contact with some 
_ ject which may serve as a support. While this correlation § 
an obvious advantage, yet it must be borne in mind tit 
a support should it meet one. It is not necessary to SUPP 
however, that the tendril has reached the stage of the high 
possible usefulness to the plant. ho 
When the moving tendril, after it has attained a length® 
4 or 5, brings its sensitive surface in contact wit 
which acts as a stimulus, a curve is formed at the 
contact in a time varying from 30 seconds to 2 mint light 
this happen in the early stages of growth, the curve ee 
the tissues are weak, and the tendril is dragged past ge 
from the support. Should the tendril have reached oo 
proximately mature stage, the curve will be formed give 
rapidly, and the strengthened tissues hold the hook form ie 
to it, and curve still further around the object. 1 a 
a rigid pole with a rattan cane, the curve formed eo pol 
ilar to that of the young tendril, and if we strike tet 
with a rope one end swinging free, the curve © 
tendril will be obtained. to wht 
In this connection it was thought important to none tino 
extent the tendril would respond to various kinds nee , 
Drops of water at ordinary temperature thrown eit oa ; 
ly or forcefully against the tendrils produced n° ; 
f the matt 
The contact of the ordinary metallic salts acted “ ot 
if the tendril were submerged in these liquids t 
osmotic action quickly caused curves. * 
*Climbing Plants, p. 153. Vines: Phys. of Plants, p. 486. 
