CLASSIFICATION OF PLANTS. TAXONOMY. 291 



the dicotyledons constituted the most highly organized group 

 of plants. He was, however, inclined to consider the monocoty- 

 ledons as the higher group. This author maintains that certain 

 families have become extinct, and therefore the phylogenetic con- 

 nection is no longer directly visible. Should this connection be 

 visible we would find, according to Nageli, the lower uniting 

 branches of the phylogenetic tree ; these lower branches have 

 become extinct. All this assumption is pure speculation. It is 

 not probable that a system of natural descent will ever be estab- 

 lished. Since Nageli desires to establish such a system, he must 

 assume the original existence of such extinct plant-groups, of 

 which even palaeontology reveals no record. 



Natural in the sense of according to nature (not in the sense 

 of according to a natural descent) is that arrangement of plants 

 which proceeds from simpler forms to those more complicated. 

 We may also say that the arrangement of series from " lower " to 

 "higher" is natural; but not from "imperfect" to "perfect." 

 (It would be wrong and meaningless to say an alga is imper- 

 fect because it lacks vascular bundles ; the algse do not require 

 such organs.) The arrangement of plants into cellular plants 

 and vascular plants, into cryptogams and phanerogams, into 

 thallophytes and cormophytes (plants with stems and leaves), 

 seems according to nature. Not any observed facts of a natural 

 descent, but our reasoning faculty, leads us to make such classi- 

 fications. It is a spiritual bond which unites all organisms. 

 This bond is the Idea of the Creator. 



