326 THE RUSTS OF NOVA SCOTIA. FHASER. 



the mycelium produced by basidiospore infection develops 

 pycnia followed by aecia, later the urediniospores appear, and 

 finally the teliospores. Any of these forms may be omitted 

 except the teliospores and basidiospores. The Roman numerals 

 I, II, III, are used to represent, respectively, the aecia, 

 uredinia and telia, and a cipher is used for the pycnia. The 

 order of development and the suppression of the spore forms 

 may be represented as follows : 



Complete series, 0, I, II, III. 



Uredinia wanting, 0, I, , III. 



Aecia wanting, 0, , II, III. 



Aecia and uredinia wanting, 0, , , III. 



~Noi enough attention has been given to the presence or 

 absence of the pycnia to be sure of the number of series, but 

 it is probable that there is also the following series: 



Pycnia and aecia wanting, , , II, III. 



Pycnia, aecia and uredinia wanting, , , , III. 



Schroeter has proposed names for the different types of 

 association of spore forms. Taking the genus Puccinm for 

 example, and it may be used for other genera as well f the types 

 would be as follows : 



Eu-puccinia, complete series, 0, I, II, III. 



Puccini opsis, uredinia omitted, 0, I, , TIT. 



Brachy-puccinia, pycnia and aecia wanting, , , IT, III. 



Micro-puccinia, pycnia, aecia and uredinia wanting, , , 

 , III. (Teliospores germinating only after a period of rest). 



Lepto-puccinia, pycnia, aecia and uredinia wanting, , , 

 , III. (Teliospores germinating immediately). 



Duggar suggests terms applicable to all genera having 

 similar spore forms, and- at the same time expressing 

 heteroecism and autoecism. He employs the word uredo as the 

 common root in combination with the prefixes used by 

 Schroeter. Thus a form that is eu-heteroecious will be termed 



