o 



2 2 Description of Plates. 



Fig. 12. — Promycelial spore emitting a germ-tube, x 500. C. B. P. 



P"ig. 13. — Promycelial spore producing a secondary promycelial spore in 

 water. X 500. C. B. P. 



Fig. 14. — Ustilago longissinia. Teleutospore just beginning to germinate. 

 X 500. C. B. P. 



Fig. 15. — The same a little later, showing the septation of the promycelium 

 and the separation of the promycelial spore. X 500. C. B. P. 



Fig. 16. — The same after two promycelial spores have been thrown off, and 

 a third is almost ready to be so. X 500. C. B. P. 



Fig. 1 7 . — Ustilago kiilmcana. Teleutospore germinated, showing the promy- 

 celial spores in whorls on the promycelium. X 350. Brefeld. 



Fig. 18. — Ustilago scabiosa: on Scabiosa arveusis, twelve hours after germi- 

 nation in water (September i, 1884). X 500. C. B. P. 



Fig. 19. — Ustilago major on Silene otitcs, gathered near Paris, October, 

 1887 ; germinated at the beginning of November. Twenty hours in water, 

 showing the promycelium, which has nearly attained its full development. 

 X 500. C. B. P. 



Fig. 20. — The same at twenty-four hours, having become septate, x 500. 

 C. B. P. 



Fig. 21. — Teleutospore with promycelium still attached (thirty-six hours), 

 which has produced a promycelial spore at its apex. This is quite an excep- 

 tional circumstance with this species. X 500. C. B. P. 



Fig. 22. — Three promycelia which have fallen off the teleutospores (twenty 

 four hours), x 500. C. B. P. 



Figs. 23-25. — Three promycelia which have produced promycelial spores 

 both terminally and laterally, after having fallen away from the teleutospores 

 (forty-eight hours), x 500. C. B. P. 



Fig. 26, 27. — Spore-balls of Urocystis primulicola, germinating (August 31, 

 1884) after forty-eight hours in water. They have emitted promycelia, probably 

 from the central spores — but on this point I was unable to satisfy myself, — which 

 have given origin to promycelial spores, one of which (Fig. 27) has produced a 

 secondary promycelial spore. X 475. C. B. P. 



Fig. 28. — Two promycelial spores conjugating, after fifty hours in water, 

 x 500. C. B. P. 



Fig. 29. — Two promycelial spores which have become vacuolate and 

 septate, after two hundred and sixty-four hours in water. X 500. C. B. P. 



Fig. 30. — Promycelial spore emitting a germ-tube, after one hundred and 

 sixty-eight hours in water, x 500. C. B. P. 



!*'£• 31- — Urocystis anemones. Teleutospore germinating in water, Novem- 

 ber 25, 1884. X 475. C. B. P. 



Fig. 32. — Two promycelial spores of the same conjugating. x 500. 

 C. B. P. 



Fig. 33. — Two promycelial spores of the same which have become vacuo- 

 late and septate, x 500. C. B. P. 



Fig. 34. — Spore-ball of Urocystis Jischeri, one teleutospore of which has 

 germinated. X 500. C. B. P. 



Fig. 35. — Three promycelial spores of the same. X 500. C. B. P. 



