SECT. I. THE FLOWER. 107 



In their aggregation they are distant, as in Lycopus Aggrega- 



, T> i lion. 



europceus ; or contiguous, as in the Kaspbeny; or 

 crowded, as in Ranunculus ; or imbricated, that is 

 overlapping one another like the tiles of a roof, as 

 in Magnolia. In their position they are opposite, 

 that is facing the petals, as in the Lily ; or alternate, 

 that is inserted between the petals and facing the 

 divisions or segments of the calyx, as in Borage. 



On this last circumstance Linnseus founds his Alterna- 

 rule for distinguishing the calyx from the corolla, t he seg- 

 which is as follows : The stamens alternate with "^0- 

 the segments of the corolla, but face the seg- rolla - 

 ments of the calyx.* This rule holds good, no 

 doubt, in a great many cases, but is, like all other 

 rules on the subject, loaded with a variety of excep- 

 tions, of which the example of the Lily just now 

 quoted is one ; unless we are with Jussieu to call its 

 single envelope a calyx. There are besides a great 

 many cases in which the rule cannot be at all ap- 

 plied ; because the number of stamens does not 

 always correspond to that of the segments of the 

 calyx and petals of the corolla, as may be seen by 

 looking into a flower of the genus Ranunculus^ 

 or into almost any other flower of the class Poll/- 

 andria, where the stamens are crowded together so 

 as to face both the segments of the one and petals of 

 the other, and consequently to form no mark of dis- 

 tinction in cases of doubt. 



The stamens, though very different in their shape Relation 



to petals. 

 * Phil. But. sfcct. <)0. 



