74 MK. DAEWIN ON" CLIMBING PLANTS. 



Echinocystis lohata. — I made numerous observations on this 

 plant (raised from seed sent me by Prof. Asa Gray), for here I 

 first observed the spontaneous revolving movement of the inter- 

 nodes and of the tendrils ; and knowing nothing of the nature of 

 these movements, was infinitely perplexed by the whole case, and 

 by the false appearance of twisting of the axis. My observations 

 may now be greatly condensed. I recorded thirty-five revolutions 

 of the intemodes and tendrils ; the slowest rate was 2h., and the 

 average, with no great fluctuations, was Ih. 40m. for each revolu- 

 tion. Sometimes I tied the internodes, so that the tendrils alone 

 moved; at other times I cut ofi" the tendrils whilst very young, so 

 that the internodes revolved by themselves ; but the rate was not 

 thus afiected. The course generally pursued was with the sun, but 

 often in the opposite direction ; sometimes the movement during 

 a short time would either stop or be reversed ; and this apparently 

 resulted from the interference of the light, shortly after the plant 

 was placed close to a window. In one instance, an old tendril, 

 which had nearly ceased revolving, moved in one direction, whilst 

 the young tendril above moved in the opposite direction. The 

 two uppermost internodes alone revolve ; as the internodes grow 

 old, the upper part alone moves. The summit of the upper 

 intemode made an ellipse or circle about 3 inches in diameter, 

 whilst the tip of the tendril swept a circle 15 or 16 inches in dia- 



meter. 



intemodes 



successively curved to all points of the compass ; and often in 



with 



tendril, at about 45 

 vertical. There was something in the appearance of the revolving 

 internodes which continually gave the false impression that their 

 movement was due to the weight of the long and spontaneously 

 revolving tendril; but, on suddenly cutting off" the tendril with a 

 sharp scissors, the top of the shoot rose very little, and went on 



tendrils 



d 



I 



repeatedly saw that the revolving tendril, though inclined 



45 



(in one case of only 37°) above the horizon, in 



course stiffened and straightened itself from tip to base, and became 



modified flower-peduncles, as is certainly the case with the tendrils o: 

 flowers. Mr. E. Holland (Hardwicke's ' Science-Oossip,' 1865, p. K 

 that " a cucumber grew, a few years ago, in my own garden, where ( 

 short prickles upon the fruit had grown out into a long curled tendril 



