PRACTICAL POLLINATION 239 



declared themselves independent of the plant- 

 insect union. 



Parts of this nonunion clan are the entire races 

 of lowly mosses and lichens ; a goodly number of 

 aquatic forms that maintain the appearance and 

 manner of their remote ancestors; and the 

 familiar tribe of ferns; and the trees which 

 depend mainly upon the wind. 



Of these, the ferns, mosses, and other forms 

 less familiar to the amateur, have obstinately 

 retained throughout the ages the primeval habit 

 of propagating their kind, not with immobile 

 pollen grains, but with the aid of self-moving 

 germ cells. These motile germ cells, of micro- 

 scopic size, find their way through the water — 

 supplied in case of land plants by a film of rain 

 or of dew — from one plant to another, and effect 

 cross-fertilization without calling in the aid of 

 any allies. They do not need to attract insects, 

 and so they have not adopted the system of 

 advertising through the development of large 

 and showy blossoms and nectar cups to which 

 the members of the plant-insect alliance are 

 obliged to resort. But if the lowly plants thus 

 maintained their independence, they have done so 

 at a very great sacrifice. 



They are not more independent than they are 

 unprogressive ; and indeed they are unprogres 



