96 THE AMERICAN BOTANIST 



There are two objections to this scheme, namely, the 

 greater convenience of the old system for thouglit and teach- 

 ing, and the questionable validity of fossil evidence in the 

 classification of living plants. 



The first objection applies equally to all attempts to 

 change from an outgrown or erroneous system to a new one. 

 Those who are accustomed to any system, feel that it is more 

 convenient for thought and teaching than any other. Additi- 

 onal years of experience convince me that the proposed new 

 system is much easier and simpler for beginners than the old. 

 I feel quite certain that this would prove true wherever this 

 arrangement is tried. 



The serious question is whether or not the fossil series 

 can he drawn upon for light on the classification of living 

 forms, or, to put it most baldly, whether fossil evidence can 

 be used to break up what now appear to be homogeneous 

 groups. In short, is our classification to be rigidly phylogene- 

 tic, or may it run crosswise of phylogeny whenever we believe 

 a cross course is more convenient for thought and teaching? 



If I understand the trend of thought, it is accepted that 

 classifications should lie, as far as our knowledge goes, phylo- 

 genetic. Presumably all who accept the doctrine of descent are 

 striving toward this end. If so, then correct thinking and 

 correct teaching must of necessity follow phylogenetic lines, 

 whether it is convenient or not. And in the end, the correct 

 way must be the convenient way. 



There still remain however certain questions of the 

 grouping of forms. An example will illustrate one of these. 

 The bush lima bean originated about 1890 from three dis- 

 tinct climbing or "pole" limas : 



Sieva bean gave Henderson's bush lima. 



Potato lima gave Kumerle bush lima. 



