PROTOBASIDIOMYCETES 



437 



tongue-shaped bodies .5-. 7 mm. high, opening by an irregular rup- 

 ture of the peridium. The spores are, according to Arthur, coarsely 



verrucose with deciduous tuber- 

 cles, except along one narrow 

 line, where tubercles fail. 



The uredospores are produced 

 in orange-yellow sori, which soon 

 fade to nearly white. They are 

 generally ellipsoidal, measuring 

 27-30 x 17-22 /*. The teleuto- 

 spores are borne in crowded 

 waxy masses, and are at maturity 

 a chain of four basidial cells within 

 a somewhat gelatinized common 

 wall. They are sessile, 55-80 x 

 15—23//., and the cell wall at the 

 apex is generally swollen, often 

 13. Coleosporium Senec,on,s attaining a maximum thickness 

 (i after Tulasne) of 30— 40 //.. 



Fig. 



XXVIII. RUST OF POPLAR 



Melampsora tremula? Tul. 



Tulasne applied the above name to a rust of the poplar (Popidus 

 tremula) occurring throughout a considerable range in Europe. 

 It would seem 

 that this name 

 would now in- 

 clude at least 

 three forms, or 

 species, as dis- 

 tinguished by 

 Klebahn, viz., 

 Melampsora Pinitorqua 

 Rostr., Melampsora 

 Larici-tremula Kleb., 

 and Melampsora Mag- 

 nusiana Wagn. These 



Fig. 214. Melampsora tremula*. : Uredospores 

 and teleutospores 



