18 PLAHT EELATIONS. 



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

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

 exposed. 



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



Fii:, 11. A i^roiip of livc-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, anil 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 leuves may bo oli.^erved by 

 Iddking down upon them from aljovo (.sec Fig. 9), as in some 

 of the early buttercups wlii(-li are so low that the large 

 leav(!S would seriously shade one another, except that the 

 lower leaves have loiigef petioles than the upper, and so 

 reach beyond the shadow. 



