93 







demands that such a natural system be a static one l) like BENTHAM- HOOKER'S 

 or ENGLER'S, and that there is possible only one true ideal system, to which, 

 however, we are as yet far from attaining, as but one phylogenetic tree is 

 possible 2) . Much against my will, I have come to entertain strong doubts as 

 to the effectiveness of the modern systernatizers' effort to attain to the ideal 

 system ; and my twenty year's experience in systematic botany has steadily 

 led me into quite a different channel of thought. Tin's I now venture to make 

 public, though I am aware that it will meet with a great deal of opposition. 

 All systematizers regard the natural system as a static one with a definite 

 form and believe that all species, genera or families have their fixed natural 

 positions, so as to be arranged between this and that, according to their 

 natural relations. My idea is quite different from this cm-rent opinion. I 

 regard the natural system as a dynamic one, changing with the view of the 

 systematize!' and subject to alteration, according to the way in which it is 

 considered, and I believe that none of the species, genera or families has a 

 fixed natural position, but has changeable positions, subject to alteration 

 according to the criterion for comparison. It is neither natural nor necessary 

 that a spscies should in all cases be arranged between this limit and that ; 

 but should be placed between this and that according to one view, or between 

 another this and another that according to another view. In the present paper, 



1) Among the literature which treats of the principle of natural classification, I may men- 

 tion the following works : 



DARWIN, C. On the Origin of Species, (New York, 1890) ; Divergence of Character, anil The 

 Probable Effects of the Action of Natural Selection through Divergence of Character and Extinc- 

 tion, on the Descendants of a Common Ancestor, 1. c. pp. 86-97 ; Classification, 1. c. pp. 303-381. 



HAECKEL, E. Prinzipien tier Generellen Morphologic der Organismen (Berlin 1906) ; Das 

 naturliche System als Stammbaum (Prinzipien tier Klassifikation), 1. c. p. 390. 



ENGLEB, A. Erlauterungen zu der Ubersicht iiber die Embroyophyta Siphon ogama, in den 

 Natiirlichen Pflanzenfamilien, Nachtragen zum II.-IV. Teil, (1897), pp. 358-380. 



, . Prinzipien der Systematischen Anordnung, im Syllabus der Pflanzenfamilien, 



siebente Auflage, Berlin, 1912. 



HALLIEK. H. Provisional Scheme of the Natural (Phylogenetic) System of Flowering Plants, 

 in the New Phytologist, Vol. IV., No. 7, (July, 1905), pp. 151-162. 



, . Ein Zweiter Entwurf des naturlichen (phylogenetischen) Systems der Bliiten- 

 pflanzen, in den Berichte der Deuts^hen Bot. Gesellsch. XXIIT., 2, pp. 85-91. 



LOTSY, J. P. Vortrage uber Botanische Stammesgeschichte, I., Jena, (1907). 



WETTSTEIN, R. Handbnch der systematischen Botanik (Zweite Auflage, 1911); Allgemeincr 

 Teil, 1. c. pp. 1-49. 



2) HALLIEB, H. Provisional Scheme of the Natural System, I.e. p. 152. 



