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 

 27-30x17-22^. 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, 5 5-80 x 

 1 5 -2 3 /A, and the cell wall at the 

 apex is generally swollen, often 

 FIG. 213. COLEOSPORWM SENBCIONIS attaining a maximum thickness 

 (b after Tulasne) of 30 40 {JL. 



XXVIII. RUST OF POPLAR 

 Melampsora tremuhe Tul. 



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

 ircmnlii) 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., 



I.arici-trcinulie Kiel)., 



and Melampsora JA?v- FIG. 214: MBLAMPSORA TREMVLA: I'KKD.>SI'<>RI-:S 



nnsiana \Yagn. The- AND TELEUTOSI-OKES 



