115 



of my reasons for tliis statement, wliile reviewing and criticizing Engler's 

 principle of uatural classification and his sysfcera. 



7. Eeview of, and critical remarks on Engler's principles 



AND HIS SYSTEM OP THE ANGIOSPERMS. 



a. Engler's principles OF SYSTEMATIC arrangement'\ 

 Speakiug conclusivelj, liis principles are those of his system, but not 

 those of what I shall call the natural system. I shall now take up this 

 matter section by section. In the first section Engler says : — ■ 



Das Streben der "wissenschaftlichen Klassifikation der Pflanzen oder der botanischen 

 Systematik ist zunKchst darauf gerichtet, die Pflanzenformen nach ihrer natiir- 

 lichen Verwandtschaft in Gremeinschaften niederen und hoheren Grades (in 

 Arten, Grattungen, Familien, Familienreihen oder Ordnungen, Klassen, Abteilungen) zu 

 grupj)ieren.2) 



Here he speaks of " natural affinity " (Natiirliclie Verwandtschaft), the true 

 meaning of which is certainly blood - relationship. But what systematizers can 

 treat directly or are treating practically is constitutional resemblance instead 

 of blood - relationship. The latter is to be found directly and exactly only in 

 a census register or in such a case as Engler refers to in § 2 ; it can not be 

 ascertained generally. We are, therefore, obliged only to infer blood - relation- 

 ship through the observations of constitutional resemblances, assuming that 

 the former is in agreement with the latter (but, in reaHty, they need not 

 agree). As the resemblances are, according to the participation theory which 

 I have referred to before, manifested by the participation of genes, Engler's 

 affinity - group (Verwandtschaftkreis) is uothing but a collection of membei^s 

 marked by one or more genes shared in the members, Tlie group is, there- 

 fore, as I have said before, a dynamic one changeable according as diiferent 

 genes are taken as criteria. Here, it is clear that Engler undoubtedly 

 means by affinity-group a static one unchangeable no matter in what way 

 it is regarded. According to my way of thinking, the existence of such a 

 definite group is impossible. Now, let us think of a case in which we could 



1) Englek, A. — Prinzipien der Systemiitischen Anordnung, im syllabTis der Pflanzenfamilien, 

 7-Aufl. (1912) pp. VnL-XXIL 



2) Engleb, A. — 1. c. p. VIIL 



