HISTORY OF BOTANY. 



method, that this division according to the cotyledons is of a higher 

 order than the other divisions according to number ; and corresponds 

 to a distinction in the general structure and organization of the plant, 

 The apprehension of the due rank of this distinction has gradually 

 grown clearer. Cuvier 9 conceives that he finds such a division clearly 

 marked in Lobel, in 1581, and employed by Ray as the basis of his 

 classification a century later. This difference has had its due place 

 assigned it in more recent systems of arrangement ; but it is only 

 later still that its full import has been distinctly brought into view. 

 Desfontaines discovered 10 that the ligneous fibre is developed in an 

 opposite manner in vegetables with one and with two cotyledons ; 

 towards the inside in the former case, and towards the outside in the 

 latter ; and hence these two great classes have been since termed endo- 

 genous and exogenous. 



Thus this division, according to the cotyledons, appears to have the 

 stamp of reality put upon it, by acquiring a physiological meaning. 

 Yet we are not allowed to forget, even at this elevated point of gene- 

 ralization, that no one character can be imperative in a natural method. 

 Lamarck, who employed his great talents on botany, before he devoted 

 himself exclusively to other branches of natural history, published his 

 views concerning methods, systems, 11 and characters. His main 

 principle is, tltit no single part of a plant, however essential, can bean 

 absolute rule for classification ; and hence he blames the Jussieuian 

 method, as giving this inadmissible authority to the cotyledons. 

 Roscoe 12 further urges that some plants, as Orchis morio, and Limodo- 

 rum verecundum, have no visible cotyledons. Yet De Candolle, who 

 labored along with Lamarck, in the new edition of the Florc Fran- 

 paise, has, as we have already intimated, been led, by the most careful 

 application of the wisest principles, to a system of Natural Orders, of 

 which Jussieu's may be looked upon as the basis ; and we shall find 

 the greatest botanists, up to the most recent period, recognizing, and 

 employing themselves in improving, Jussieu's Natural Families ; so 

 that in the progress of this part of our knowledge, vague and per- 

 plexing as it is, we have no exception to our general aphorism, that no 

 real acquisition in science is ever discarded. 



9 Hist. Sc. Nat. ii. 197. 10 Hist. Sc. Nat. i. pp. 196, 290. 



11 Sprengel, ii. 296 ; and, there quoted, Flore Fran^aise, t. i. 3, 1778. Mem. 

 A>- P. 1785. Journ. Hist. Nat. t, i. For Lamarck's Methods Analytique, M* 

 Dumeril, Sc. Nat. i. Art. 390. 



U< -cue, Linn Tr. vol. xi. Cuscuta also has no cotyledons. 



