Chap. n. MAUEANDIA. 69 



these sides ; in 24 hrs. subsequently, they straightened 

 themselves. Next day they were rubbed on the 

 opposite sides, and they became perceptibly curved 

 towards these sides. Two other and younger pe- 

 duncles (three-fourths of an inch in length) were 

 lightly rubbed on their adjoining sides, and they be- 

 came so much curved towards one another, that the 

 arcs of the bows stood at nearly right angles to their 

 previous direction ; and this was the greatest movement 

 seen by me. Subsequently they straightened tbem- 

 selves. Other peduncles, so young as to be only 

 three-tenths of an inch in length, became curved when 

 rubbed. On the other hand, peduncles above IJ inch 

 in length reqtdred to be rubbed two or three times, 

 and then became only just perceptibly bowed. Loops 

 of thread suspended on the peduncles produced no 

 effect ; loops of string, however, weighing '82 and 1*64 

 of a grain sometimes caused a slight curvature ; but 

 they were never closely clasped, as were the far lighter 

 loops of thread by the petioles. 



In the nine vigorous plants observed by me, it is 

 certain that neither the slight spontaneous movements 

 nor the slight sensitiveness of the flower-peduncles 

 aided the plants in climbing. If any member of the 

 Scrophulariaceae had possessed tendrils produced by 

 the modification of flower-peduncles, I should have 

 thought that this species of Maurandia had perhaps 

 retained a useless or rudimentary vestige of a former 

 habit ; but this view cannot be maintained. We may 

 suspect that, owing to the principle of correlation^ 



