132 LETTER XXXVIII. 



s s s s s 



p p p p p 



p p p p p 



s s s s s 



c c c c c 



And other changes in proportional numbers would be 

 productive of corresponding alterations of position. 

 These differences are found of great importance in sys- 

 tematic Botany, and every good writer pays the most 

 careful attention to them. Their value is very much 

 increased by considering the nature and degree in 

 which abortion takes place, and observing, by the 

 manner in which it affects the usual order of succes- 

 sion, whether it indicates a tendency to the production 

 of more rows of parts than actually develope, or to the 

 suppression of a portion of those rows that are in part 

 completed, and what relation is really borne to each other 

 by the parts that appear, and those that do not develope. 

 If you look into this subject practically, you will find 

 that the abortion of particular organs, or rows of 

 organs, is, in a greatnumber of cases, the most unerring 

 sign by which certain natural groups are distinguished, 

 and that the importance of the abortions, in a systematic 

 view, is in proportion to the degree in which they derange 

 the symmetry of the flower, or cause a deviation from 

 regular structure. I cannot do better than give you 

 several instances of this, by tables similar to the pre- 

 ceding, in which the letters have the same value as 

 before ; those which indicate partial abortions being 

 printed in italics, and in a smaller type, and total abor- 

 tions being represented by dots. 



