THE QUEST OF PHYLETIC LINES 



FREDERICK ORPEX BOWER 



University of Glasgow, Glasgow, Scotland 



For over half a century the Darwinian aspect of descent has 

 been before the mind of biologists, and though more recent devel- 

 opments of method and thought may have tended to modify or 

 extend our conception of the mechanism of evolution, still the 

 central problem remains the same, viz., to understand how the 

 various living things we see came to be what they are, and where 

 they are. It is natural that such problems should take a strong 

 hold on active intellects — they engender keen enthusiasm, and so 

 strong may this be that it is apt at times to outrun the cooler canons 

 of criticism. One sees a theory promulgated, and the enthusiast 

 may accept it with a sense of assurance that it is the true interpre- 

 tation of the facts which it seems to cover. The detached cynic, 

 regarding it with cooler and more critical gaze, may probably 

 hold aloof, with a sense that the explanation is too simple and too 

 direct, or that the substratum of fact is insufficient to bear the 

 weight of the superstructure of theory. 



Seeing such diverse estimates made, and strongly upheld or, 

 it may be, repudiated — estimates that are referable in their 

 origin sometimes to the temperament as much as to the intellect 

 of their respective adherents — suggests a revision of the ground 

 work upon which such opinions should rest. Whether our tem- 

 perament be sanguine or phlegmatic, and in relation to it our 

 arguments tend to be constructive or destructive, it is well to see 

 clearly the foundations on which we build. Accordingly it seems 

 to be worth while to examine what are the fundamental data 

 upon which so many are busily engaged in constructing the mod- 

 ern phylogeny of the plant kingdom. 



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THE PLANT WORLD, VOL. 15, XO. 5, MAY, 1912 



