26 
PLANT STUDIES 
FIG. 20. A spray of maple, showing the adjustment of the leaves in size and position 
of blades and length of petioles to secure exposure to light on a horizontal stem. 
After KERNER. 
etc., as to give ample evidence of the effort put forth by 
plants to secure a favorable light-relation for their foliage 
FIG. 21. Two plants showing adjustment of leaves on a horizontal stem. The plant 
to the left is nightshade, in which small blades are fitted into spaces left by the 
large ones. The plant to the right is Selaginella, in which small leaves are dis- 
tributed along the sides of the stem, and others are displayed along the upper sur- 
face. After KEENER. 
