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demands that such a natural system be a static one? like BENTHAM- HooKeEr’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”. Much against my will, I have come to entertain strong doubts as 
to the effectiveness of the modern systematizers’ 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. This 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 current opinion. I 
regard the natural system as a dynamic one, changing with the view of the 
systematizer 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 species 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, and The 
Probable Effects of the Action of Natural Selection through Divergence of Character and Extinc- 
tion, on the Descendants of a Common Ancestor, l. c. pp. 86-97; Classification, 1. ¢. pp. 363-381. 
Hacks, E.— Prinzipien der Generellen Morphologie der Organismen (Berlin 1906); Das 
natiirliche System als Stammbaum (Prinzipien der Klassifikation), 1. c. p. 390. 
Eneter, A. -- Erliuterungen zu der Ubersicht iiber die Embroyophyta Siphonogama, in den 
Natiirlichen Pflanzenfamilien, Nachtrigen zum I-IV. Teil, (1897), pp. 358-389. 
» —---Prinzipien der Systematischen Anordnung, im Syllabus der Pdanzenfamilien, 
siebente Auflage, Berlin, 1912. 
: Hater, H. — Provisional Scheme of the Natural (Phylogenetic) System of Flowering Plants, 
in the New Phytologist, Vol. IV., No. 7, (July, 1905), pp. 151-162. 
la. — Ein Zweiter Entwurf des natiirlichen (phylogenetischen) Systems der Bliiten- 
pfanzen, in den Berichte der Deutschen Bot. Gesellsch. XXIII, 2, pp. 85-91. 
Lotsy, J. P. — Vortrige iiber Botanische Stammesgeschichte, L, Jena, (1907). 
Werrtsteix, R.— Handbuch der systematischen Botanik (Zweite Auflage, 1911); Allgemeiner 
Teil, 1. ¢. pp. 1-49. 
2) Haxurer, H. — Provisional Scheme of the Natural System, Lc. p. 152. 
