DI-MOEPHISM. 39 



not a genus by itself, but are organs in tlie develop- 

 ment of some other germs and species, possessing 

 its spermogonia, its ^cidium, its Uredo, and its 

 spores, properly speaking ; whilst in others the 

 UrecZo-form, the Puccinia-iorm, and the JEcidium- 

 form may alternate. It is not our intention to 

 enter deeply upon the discussion of this subject, of 

 so little interest to the beginner, and so out of 

 place in an introduction to the study. That forms 

 and conditions are multifarious, and that an entire 

 revision of the classification is inevitable, are facts 

 which do not require many words to estabHsh. 

 Already it is to be feared that in this brief chapter 

 we have said too much, and must recommend its 

 perusal again, when the names and characters of 

 the genera aUuded to have been rendered more 

 familiar. 



It could scarcely have been permitted that the 

 student should go far without being cautioned that 

 there is such a thing as di-morphism in microscopic 

 fungi ; and the explanation of such a phenomenon 

 must presuppose a certain amount of knowledge 

 which, thus far, the reader could not have acquired. 

 Hence an anomaly, to escape from which an ulti- 

 mate return to the subject will be necessary. 



In a recent account of Dr. de Bary's experi- 

 ments,* an interesting history is given of the 

 development of a rust-like fungus, which is common 



* De Baiy — "Annales des Sciences Nr^turelles," ser. 4, vol. xx. 



