EXPLANATION OF PLATE. 



7. Part of a section through a sorus of Coleospori urn sonchi, Lev., from Sonchus oleraceus, L- 

 b, multicellular spores ; f, promycelial hyphcB issuing from the germinating spores ; 

 s, promycelial spores. 



2 and 3. Promycelial spores of Coleosporium tussilaginis, Pers., germinating. 



4. Germinating promycelial spore of Coleosporium sonchi, Lev., -which has produced a 



secondary promycelial spore; x 460. 



5. Section through a sorus of Melampsora solid na, Lev.u, uredospores; p, m, teleuto- 



spores ; x 240. 



6. Four spores from a sorus of Coleosporium tussilaginis, Lev. One of the two that have 



germinated has produced promycelial spores at the ends of the promycelial hypha ; 

 x320. 



7. Promycelial spore that has germinated and produced a secondary promycelial spore ; 



x340. 



8. Uredospores and paraphyses of Melampsora betulina, Desm., from Betula alba, L.; 



x330. 



9. Uredospore of Melampsora salicina, Lev., germinating. 

 70. The same as 9. 



11. Uredospore of Melampsora populina, Lev., germinating. 



72. Promycelial spore of Coleosporium tussilaginis, Lev., germinating; x 330. 



73. Part of a section through a sorus of Melampsora betulina, Desm., from Betula alba. 



r, hyphae; b, teleutospores ; s, promycelial spores ; e, stomatum; p, parenchyma. 



74. Promycelial spores of the same fungus beginning to germinate ; x 460. 



cr 



UF 



