1(! 



PLANT STUDIES 



find the lowest leaves of a plant the largest and with the 

 longest ])etioles, even when the leaves are not very close 

 together on the stem. 



It mnst not be supposed that hy any of these devices 

 shading is absolutely avoided. This is often impossible and 

 sometimes undesirable. It simply means that by these 



Fig. 9. A plant {SaintpauVut) witli the lower petioles elongated, tlirustiiig the blades 

 beyond the shadow of the upper leaves. A loose rosette. 



arrangements the most favorable liglit-relation is souglit by 

 avoiding too gi'eat shading. 



20. Direction of leaves. — Not only is the jiosition on tlie 

 stem to be oljserved, but tlic direction of leaves often shows 

 a definite relation to light. It is a very common thing to 

 find a plant with a cluster of comparatively largo leaves at 

 uv near the base, where they are in no danger of shading 

 other leaves, and with tlie stem leaves gradually becoming 



