270 EXPERIMENTS WITH PLANTS 



in water-plants there is no problem of this sort, since 

 the water supports them, and consequently we find 

 them almost destitute of woody fiber. 



What plants get their leaves up into the sunlight 

 with the greatest rapidity and the least outlay of 

 material? Consider the twining and climbing plants in 

 this connection (see Fig. 151) . The problem of climb- 

 ing is one that has been solved by various plants in 

 a great number of different ways, so that it would 

 hardly seem possible to suggest other solutions than 

 those actually found in nature. 



Beginning with the simplest cases, we have what 

 we may call weaving plants, which weave themselves 

 in and out among the branches of other plants and 

 cling by means of their branches and straight or 

 slightly curved leaf -stalks or by means of hooks, 

 spines, etc. As examples of this class of climbers, 

 study the climbing Roses, Blackberry, Raspberry, 

 Jasmine, etc. How does the plant behave when it first 

 starts up from the ground ? Where does it begin to 

 branch 1 How does it reach or find the support ? How 

 does it cling to it? Does it always "prevent its leaves 

 from being shaded by the plant which supports it? 

 Do you think that its stem seeks the light ? 



More special and elaborate adaptations for climbing 

 are found in tendril - bearing plants. The leaf -stalk in 

 many cases acts as a tendril, as in the Nasturtium, 

 Clematis and the Potato vine ; in other cases the leaf- 



