JMclainpsora. 241 



Synonym. 



Melampsora tremulcs, Tul. Ann. Sc. Nat., 2nd series, p. 95. 

 Cooke, "Hdbk.," p. 522; "Micro. Fungi," 4th edit, p. 219. 

 Sclirot., loc. at., p. 362. 



Exsiccatt. 



Cooke, i. 85; ii. 154; "L. R," 48. Vize, "Micro. Fungi 

 Brit," 44. 



On Pop 1(1 us tremula. 

 June to November. 



Biology. — Rostrup states that the aecidiospores of this species 

 are Cceoina inercurialis and C. pinitorquum. The last-named species 

 is not British. I have applied the germinating teleutospores froni 

 P. tremula to Mercurialis pere7inis in 1883 and 1884, but could 

 obtain no result (Exp. 277-350). Although C. pinitorquum is not a 

 British species, yet I applied the germinating teleutospores of this 

 Melampsora to Pinus sylvestris (Exp. 351), but with no result. I 

 have also tried the germinating teleutospores on Orchis maculata and 

 latifolia, but with no result (Exp. 650-652, 654, 655). 



Hartig (" Allgem. Forst-und Jagdztg.," 1885, pp. 325-327) states that 

 the aecidiospores o{ M. tremulcB are Cceoma laricis, and that by apply- 

 ing the spores of C. laricis to the leaves of Populus tremula he 

 produced the Melampsora, and adds that C. laricis and C. pinitorquum 

 may either be two distinct species, or the same species modified by 

 the difference of the host-plant. I have repeated Hartig's experiments 

 on three occasions (Exp. 710, 768, 769), by placing the germinating 

 teleutospores of M. tremula on young larch-trees, but without result. 

 Professor Trail, however, finds these two species growing in company 

 near Aberdeen, 



Probably more than one species of Melampsora occur on Populus 

 tremula. 



Melampsora aecidioides. (D. C.) 



Uredospores — Sori small, roundish, surrounded by a white wreath 

 of large crowded paraphyses. Spores spherical, elliptical, or 

 ovate, 17-24 X 15-17/X. Spore-walls colourless, echinulate, 

 contents orange-red. Paraphyses clavate, 40-60 X i5-20/>(, 



Teleutospores — Forming small brown crusts. Spores cylindrical, 

 brown, cohering laterally, apex truncate, 50 X lo//. 



R 



