CHARACTERS USED IN CLASSIFICATION. 123 



155. We have found that Tournefort considered chiefly differ- 

 ent aspects and circumstances of the corolla / — Linnteus, of the 

 stamens andpistils ; — Jussieu, of the cotyledons^ and insertion of 

 the stamens. Tournefort's system was defective, as tlie forms of 

 corollas are often indefinite, and blend into those of an opposite 

 character ; that of Jussieu appears too abstract to be used inde- 

 pendently of the aid of some more simple method ; — the number 

 of cotyledons^ though a definite and important character, cannot, 

 in many cases, be determined without the slow process of wait- 

 ing for the seeds to germinate ; the insertion of stamens and of 

 the corolla often appears doubtful, even to the experienced 

 botanist. The characters used in the system of Linnaeus are 

 apparent^ referring to the numher of parts, rather than to 

 their forms or insertion / this offers to the mind something 

 positive^ which is not found in any other method. Between a 

 corolla hellform or funnelform there are many intermediate 

 forms^ which may be as much like one as the other. The in- 

 sertion over the germ or under the germ is distinct, but the 

 insertion around the germ sometimes blends with one, some- 

 times with the other mode. But, hetween one or two stamens^ 

 or 07ie or two pistils^ there is no intermediate step or gradual 

 blending of distinctions. 



The Linngean system, m jyractice^ is by no means perfect. In 

 treating of the classes in detail, we shall point out cases in which 

 it widely separates plants similar in appearance and properties, 

 and brings together, from the mere circumstance of similarity 

 in stamens, plants w^hoUy unlike in other respects. The im- 

 provements of Lindley and other botanists upon the method of 

 Jussieu, we shall hereafter consider. 



LECTUEE XXIII. 



CHARACTERS USED IN CLASSIFICATION. 



156. LiNN^us, in his "Philosophy of Botany," established 

 three kinds of characters to be used in the description of plants. 

 Factitious (or made) ; that which is, by agreement, taken as a 

 mark of distinction ; thus, certain circumstances with respect 

 to stamens and pistils are fixed upon for distinguishing classes 

 and orders. Although nature has formed these organs, the 

 arrangement of plants by their means is an invention of man, 



155. Comparative merit of the three methods— System of Linmens offers something positive— Is not 

 perfect. — 156. Three kinds of characters to be used in descriptions of plants. 



