CHYTRIDIINEAE 



75 



FIG. 19. DIAGRAM OF THE LIFE-CYCLE OF A FUNGUS, SYNCH YTRIUM 

 ENDOBIOTICUM. A, parasite with remains of flagellum still present 

 entering an epidermal cell ; B, parasite much larger with large nucleus 

 and granular plasm at the surface of and above the nucleus, the 

 lateral host-cells hypertrophied and projecting as the " rosette " ; 

 C, sorus-formation, more than half the parasite has passed out from 

 its original cell-wall ; D, first mitosis of sorus ; E, sorus completely 

 subdivided into sporangia ; F, single ripe sporangium, zoospores 

 escaping, two forming a zygote at z ; M, zygote entering epiderm 

 cell, its two flagella showing as remnants ; N, parasite grown larger 

 lies on the deep side of the host-cell nucleus, which, with those of 

 adjacent cells, is in mitosis ; O, parasite still larger with granules in 

 its plasm ; P, definite chromidia in plasm of parasite, ceUs of host- 

 plant deep to it in mitosis ; Q, parasite full-grown with large nuclear 

 cavity and nucleolus at one side of it ; rp indicates a resting period of 

 2J months ; R, ripe resting-sporangium germinating, zoospores 

 escaping. Based on K. M. Curtis's descriptions. 



