CHAP, iv Taxonomy, 1860-1900 125 



of phylogeny, and to the recognition of the fact that 

 problems of affinity are bound up with actual descent. 



Eichler's system served as the basis of the arrangement 

 proposed a little later by Warming in Denmark, and was 

 followed in the main by Engler, whose classification appeared 

 in 1892 and was very generally adopted by the end of the 

 century. His arrangement of the lower groups has 

 already been alluded to. In classifying the Phanerogams, 

 which he called Embryophyta Siphon ogama, he followed 

 his predecessors in recognizing the Gymnosperms and the 

 Angiosperms as co-ordinate subdivisions. His selection 

 of the terms Embryophyta Zoidiogama and Embryophyta 

 Siphonogama was unfortunate, as they were shown to be 

 quite inappropriate by the discovery of antherozoids in 

 certain Gymnosperms in 1895. He introduced among 

 the Gymnosperms the extinct groups Cordaitales and 

 Bennettitales, which had not been recognized by any 

 previous taxonomist. In subdividing the Angiosperms 

 he made two very unequal classes, the Chalazogamae, in 

 which the pollen tube reaches the embryo-sac by way of 

 the chalaza, being made co-ordinate with the Acrogamae, 

 which comprise the rest of the group. The necessity of 

 this is open to question, as it may be taken to be at least 

 doubtful if so purely a physiological character as the 

 mode of fertilization is of very great diagnostic value. 

 The Acrogamae were then divided into Monocotyledons 

 and Dicotyledons. Of the former Engler made ten series, 

 commencing with the Pandanales, which he held to be 

 the most primitive forms. 



In the arrangement of the Dicotyledons he abolished 

 the large inchoate group of the Monochlamydeae, and 

 distributed its members among the forms with free petals, 

 so constituting a large series, the Archichlamydeae. He 

 made but one other group, the Sympetalae, which included 

 all with united petals. Here he had a considerable follow- 



