1 34 Development of the Natural System under [BOOK i. 



have in like manner been formed by adherence of two or more 

 carpellary leaves, and concludes by pointing out the systematic 

 importance of such considerations. Further on he takes 

 occasion to speak of the significance of the relative number 

 of the parts of the flower, on which head he says much that is 

 good, but does not thoroughly investigate the matter ; it was 

 not till a later time that Schimper's doctrine of phyllotaxis 

 made it possible to express these relations of number and 

 position more precisely. 



He concludes his rules for the application of his morphology 

 to the determination of relations of affinity with the declaration, 

 that the whole art of natural classification consists in dis- 

 cerning the plan of symmetry, and in making abstraction of all 

 the deviations from it which he has described, much in the 

 same way as the mineralogist seeks to discover the funda- 

 mental forms of crystals from the many derivative forms. It is 

 obvious that all this teaching was a great step in advance upon 

 the right path, that De Candolle has here given utterance for 

 the first time to an important principle of morphology and 

 systematic botany ; nevertheless he did not succeed in always 

 consistently carrying out his own principle ; he was true to 

 himself only in the determination of small groups of relation- 

 ship ; in framing the largest divisions of the vegetable kingdom 

 he entirely lost sight of the rule which he had himself laid 

 down, that the morphological character of organs and the 

 extent to which it can be turned to account for systematic 

 purposes is entirely independent of their physiological character, 

 and that the most important physiological characters are just 

 those which are of quite subordinate importance in the determi- 

 nation of affinities. In spite of this strange inconsistency, to 

 De Candolle belongs the merit of being the first to point 

 emphatically to the distinction between morphological and 

 physiological marks, and to bring clearly to light the dis- 

 cordance between morphological affinity and physiological 

 habit; but in this discordance lurks a problem, which could 



