46 ELEMENTS OF BOTANY. 
(2) Laying hold of objects by means of tendrils or twining 
branches or leaf-stalks, as shown in Figs. 50, 31. 
(3) Twining about any slender upright support, as shown 
in Fig. 32. 
69. 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. Continued obser- 
vation soon shows that the tips of 
tendrils sweep slowly about in the air 
until they come in contact with some 
object about which they can coil them- 
selves. After the tendril has taken a 
few turns about its support, the free 
part of the tendril coils into a spizal 
and thus draws the whole stem toward 
the point of attachment as shown in 
Fig. 30. Some tendrils are leaves or 
stipules, as shown in Fig. 90; others 
are modified stems. 
70. Twiners.—Only a few of the 
upper internodes of the stem of a 
y twiner are concerned in producing the 
FIG. 30,—Coiling ofaTen. Movements of the tip of the stem. 
dril of Bryony. This is kept revolving in an elliptical 
z,portion coiled around a twig; : ashe #c 
w, w', places where direction OF Circular path until it encounters 
of coiling reverses; u, un- some roughish and not too stout object, 
2 ae tinaea ada as about which it then proceeds to coil 
itself. The direction of the coiling varies in different kinds of 
climbers, some following the course shown in the figure of the 
hop on the next page, others, as the morning-glory, taking 
the opposite course. 
71. Underground Stems.—Stems which lie mainly or wholly 
underground are of frequent occurrence and of many kinds. 
