156 TENDKIL-BEAEERS. Chap. 1Y. 



I repeated the experiment made on the Echinoci/stis, 

 and placed seTeral plants of this Passiflora so close 

 together, that their tendrils were repeatedly dragged 

 over each other ; but no curvature ensued. I likewise 

 repeatedly flirted small drops of water from a brush on 

 many tendrils, and syringed others so violently that 

 the whole tendril was dashed about, but they never 

 became curved. The impact from the drops of water 

 was felt far more distinctly on my hand than that from 

 the loops of thread (wghing -g^nd of a grain) when 

 allowed to fall on it from a height, and these loops, 

 which caused the tendrils to become curved, had been 

 placed most gently on them. Hence it is clear, that the 

 tendrils either have become habituated to the touch of 

 other tendrils and drops of rain, or that they were from 

 the first rendered sensitive only to prolonged though 

 excessively slight pressure of solid objects, with the 

 exclusion of that from other tendrils. To show the 

 difference in the kind of sensitiveness in different plants 

 and likewise to show the force of the syringe used, I 

 may add that the lightest jet from it instantly caused 

 the leaves of a Mimosa to close ; whereas the loop of 

 thread weighing ^nd of a grain, when rolled into a 

 ball and placed gently on the glands at the bases of 

 the leaflets of the Mimosa, caused no action. 



Passiflora punctata. — The internodes do not move, 

 but the tendrils revolve regularly.^ A half-grown and 

 very sensitive tendril made three revolutions, opposed 

 to the course of the sun, in 3 hrs. 5 m., 2 hrs. 40 m., 

 and 2 hrs. 50 m. ; perhaps it might have travelled more 



