SPECIFIC CHARACTERS. 57 



the idea of an Aggregate Flower (69). Our great 

 leader is the more censurable, as the Flowers and 

 Seeds of those Plants, properly studied, afford all-suf- 

 ficient Generic Characters. 



The parts of Fructification themselves, so far as 

 their differences do not enter into the Generic Cha- 

 racters, often display most excellent Specific marks. 

 Such now and then serve to divide a genus into Sec- 

 tions; as the Petals in Iris, and the Styles in Hype- 

 ricum. 



The more concise a Specific Character, the better 

 it is. As in philosophy, it is not allowed to recur to 

 two causes for the explanation of any phenomenon, 

 when one is sufficient, so if one idea will serve to di- 

 stinguish a Species, no more should be admitted. If 

 more be necessary, as is generally the case in large 

 Genera, they should be so disposed and contrasted, in 

 the several Specific definitions, as to strike the mind 

 at once forcibly and distinctly. This cannot be done 

 if characters be much extended. Linnaeus has there- 

 fore limited each definition to twelve words. There is 

 no magic in this number, but I believe it is seldom 

 icxceeded with any good effect. Much will depend, 

 after all, on the wording and construction of the sen- 

 tence. A weak character of half a dozen words may 

 be puzzling and insufficient ; while a much longer may 

 be clear, and readily conceived as well as compared, 

 at one view. 



All the terms and definitions should be precise, lite- 



