18 



PLANT RELATIONS. 



carried so far that most of the part which is covered is 

 but a stem (petiole) for the upper part (blade) which is 

 exposed. 



In many plants which do not form close rosettes a gen- 



FIG. 11. A group of live-for-evers, illustrating the rosette habit and the light-relation. 

 In the rosettes it will be observed how the leaves are fitted together and diminish 

 in size inwards, so that excessive shading is avoided. The individual leaves also 

 become narrower where they overlap, and are broadest where they are exposed to 

 light. In the background is a plant showing leaves in very definite vertical rows. 



eral rosette arrangement of the leaves may be observed by 

 looking down upon them from above (see Fig. 9), as in some 

 of the early buttercups which are so low that the large 

 leaves would seriously shade one another, except that the 

 lower leaves have longer petioles than the upper, and so 

 reach beyond the shadow. 



