GENERAL INFORMATION 111 



CLASSIFICATION OF PLANTS 



As stated in the introduction (page 2), the clas- 

 sification of grasses is based on the characters of the 

 spikelet. The classification of plants is itself but a 

 human attempt to show natural relationship, and the 

 attempt is based on knowledge of but an infinitesimal 

 part of the plant kingdom, The plants occupying 

 the earth today are the survivors of millions of 

 generations. Countless forms have become extinct. 

 Some of these are known from fossils, but far more 

 have vanished, leaving no record. Linnaeus said 

 " Nature never makes jumps. " Connecting links 

 exist or have existed between the greatest extremes. 

 When no such link is known, we conjecture that the 

 missing intermediates are among the countless ex- 

 tinct forms. Human minds approaching a given 

 problem from various angles form different con- 

 jectures; hence it is, that botanists of different 

 periods or even of the same period, have diverse 

 ideas of relationships. The species that Linnaeus 

 described under Poa, for example, are today recog- 

 nized as belonging in three genera and his species of 

 Panicum in nine genera. As a vastly greater number 

 of plants are known today, botanists have wider 

 knowledge on which to base conclusions, but the 

 main difference between the Linnaean and the 

 present-day idea of genera is due to the modern 

 concept of a genus as a network of related species as 

 contrasted with the earlier concept of a genus as a 



