STEMS. 45 
the white clover, the dandelion, the spurges, the knot-grass, 
and hundreds of other kinds of plants have found safety in 
hugging the ground. 
68. Climbing and Twining Stems.1—Since it is essential 
to the health and rapid growth of most plants that they 
should have free access to the sun and air, it is not strange 
that many should resort to special devices for lifting them- 
selves above their neighbors. In tropical forests, where the 
darkness of the shade anywhere beneath the tree-tops is so 
great that few flowering plants can thrive in it, the climbing 
plants or dianas often run like great cables for hundreds of 
FiaG. 29. — The Dandelion ; a so-called Stemless Plant. 
feet before they can emerge into the sunshine above, as those 
shown in the frontispiece have probably done. In temperate 
climates no such remarkable climbers are found, but many 
plants raise themselves for considerable distances. The prin- 
cipal means to which they resort for this purpose are : 
(1) Producing roots at many points along the stem above 
ground and climbing on suitable objects by means of these, as 
in the English ivy, Fig. 14. 
1 See Kerner and Oliver’s Natural History of Plants, vol. 1, p. 669. 
