Chap. IV. CUCUKBITACE^I. 129 



tendrils, are from 15 to 16 inches in diameter. During 

 the revolving movement, the internodes become 

 successively curved to all points of the compass ; 

 in one part of their course they are often inclined, 

 together with the tendrils, at about 45 to the horizon, 

 and in another part stand vertically up. 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 cutting off the 

 latter with sharp scissors, the top of the shoot rose only 

 a little, and went on revolving. This false appearance 

 is apparently due to the internodes and tendrils all 

 curving and moving harmoniously together. 



A revolving tendril, though inclined during the 

 greater part of its course at an angle of about 45 (in 

 one case of only 37) above the horizon, stiffened and 

 straightened itself from tip to base in a certain 

 part of its course, thus becoming nearly or quite 

 vertical. I witnessed this repeatedly ; and it occurred 

 both when the supporting internodes were free and 

 when they were tied up ; but was perhaps most con- 

 spicuous in the latter case, or when the whole shoot 

 happened to be much inclined. The tendril forms a 

 very acute angle with the projecting extremity of the 

 stem or shoot ; and the stiffening always occurred as 

 the tendril approached, and had to pass over the shoot 

 in its circular course. If it had not possessed and 

 exercised this curious power, it would infallibly have 

 struck against the extremity of the shoot and been 



