440 General Botany 



The great plant groups. We have already described two of 

 the major plant groups or phyla : the Bacteria {Schizomycetes) 

 and the Fungi (Eumycetes). In succeeding chapters the more 

 important characteristics of other major plant groups will be 

 discussed. These groups are the Algce (including several distinct 

 phyla), the Bryophytes (mosses and liverworts), the Pterido- 

 phytes (ferns, horsetails, and club-mosses), the Gymnosperms 

 (conifers and cycads), and the Angios perms (flowering plants). 



Because of the great diversity of the plant kingdom, the 

 number of groups in it is very large. For this reason only brief 

 generalized descriptions of the major groups can be given in a 

 text like this, and all consideration of some phyla must be omitted. 

 Furthermore, it may be necessary to group together other phyla 

 under series names that do not necessarily imply relationships. 

 For example, Thallophyta is often used to designate all plants 

 below the mosses and liverworts — all plants with a vegetative 

 body undifferentiated into leaf-like, stem-like, or root-like organs. 

 The algae constitute the series of chlorophyll-bearing phyla 

 placed among the Thallophyta, and the fungi include the non- 

 green phyla. Yet in grouping algae and fungi together we do not 

 mean to imply relationships between them. 



