Five-leaved Clover 363 



leaves of a branch, in their order from the base 

 to the top. They were as follows : 



3. 4. 5. 6. 7. 5. 5. 4. 



But this is a selected case, and such regular 

 examples of the expected periodicity are rarely 

 found. Often one or more of the various steps 

 are lacking, or even leaves with smaller num- 

 bers may be interspersed among those with 

 larger numbers of leaflets. But while the regu- 

 larity of the periodicity is in some degree 

 duninished by such occurrences, yet the rule 

 always holds good, when taken broadly. It 

 may be expressed by stating that the bases and 

 apices have on the average fewer leaflets on each 

 leaf than the middle parts of the stem and 

 branches, and that the number of leaflets grad- 

 uallv increases from the base toward a maxi- 

 mum, which is reached in organs on the middle 

 or upper part of the axis, and then diminishes 

 from this toward the apex. 



This periodicity is not limited to the stems 

 and branches, considered singly, but also holds 

 good in a comparison made between the 

 branches of a single stem, in regard to their rel- 

 ative places on that stem. So it is also for the 

 whole plant. The first stems, produced by the 

 subterranean axis, ordinarily show only a low 

 maximum deviation : the next succeeding being 



