LEAVES 



11 



are the largest, and the upper leaves gradually diminish 

 in size. 



(3) Rosette-habit. An extreme case of crowding is shown 

 by plants with the rosette-habit : that is, those which produce 



FIG. 6. Rosette-habit shown by mullein (4) and evening-primrose (5). 



a cluster or rosette of leaves at the base of the stem (Figs. 

 and 7). Often this rosette, frequently lying flat upon the 

 ground or upon the 

 rocks, includes all 

 the leaves the plant 

 produces. This close 

 overlapping of leaves 

 is a poor adjustment 

 to light at best, but 

 there is evident an 

 adjustment to se- 

 cure the most light 

 possible under the 

 circumstances. The 

 lowest leaves of the 

 rosette are the long- 

 est, and the upper ones become gradually shorter, so that 

 each leaf has at least a part of its surface exposed to light. 



