iv PREFACE 



Another indication of the change that has taken place 

 in the science is suggested by the fact that then the 

 Plant Kingdom was divided into the ''Phaenogams" 

 and ''Cryptogams," and that the usual sequence of the 

 study was first proper "Botany" as a course in the 

 structure, reproduction and classification of the " Phaeno- 

 gams," with a possible Anhang of " Cryptogamic Botany" 

 for such students as wished to invade this mysterious 

 realm. How completely this has given way to a more 

 scientific conception of the Plant Kingdom is shown by 

 the practical disappearance of these terms from botanical 

 literature and their relegation to more or less popular 

 usage. 



Again, it was formerly the very general practice of 

 teachers to present the subject of plant study beginning 

 with the higher plants, and indeed devoting the far 

 greater time to them, so that the sequence was from the 

 higher to the lower forms. However, with the more 

 complete acceptance of the doctrine of evolution the 

 opposite sequence from the lower forms to the higher 

 has become the general rule, since it permits greater 

 emphasis to be placed upon the progressive structural 

 changes by which higher organisms have been evolved 

 from lower. 



In the earlier period there was not yet a general agree- 

 ment as to the nature of the fungi, and their relationship 

 to the algae. They were treated for the most part as a 

 group of quite isolated plants with only obscure if any 

 relationship with other groups. They were contrasted 

 Avith other groups, little attempt being made to empha- 

 size similarities in structure, or to suggest possible genetic 

 relationships. Today, on the contrary, we constantly 

 suggest to the students the probabilities as to the origin 

 of each group of fungi. 



