STEMS 57 
74, Tendril-Climbers. — The plants which climb by means 
of tendrils are very interesting subjects for study, but they 
cannot usually be managed very well in the schoolroom. 
Fic. 29. Coiling of 
Petiole of Dwarf 
Tropeolum. 
toward the point of attachment, as shown 
Some tendrils are leaves or 
stipules, others are modified stems. 
75. Twiners.1— Only a few of the 
upper internodes of the stem of a twi- 
in Fig. 28. 
\: Continued observation soon shows that the tips 
jof tendrils sweep slowly about in the air until 
they come in contact with 
some object about which 
they can coil themselves. 
After the tendril has taken 
a few turns about its sup- 
port, the free part of the 
tendril coils into a spiral 
and thus i 
draws the <4 as. 
whole stem / 
ner are concerned in producing 
the movements of the tip of the 
stem. This is kept revolving in 
an elliptical or circular path un- 
til it encounters some roughish 
and not too stout object about 
which it then proceeds to coil 
itself. The direction of the coil- 
ing varies in different kinds of 
| 
Fic. 80. Twining Stem 
of Hop. 
climbers, some following the course shown in the figure 
1 See article on Climbing Plants, by Dr. W. J. Beal, in the American Nat- 
uralist, Vol. IV, pp. 405-415. 
