Fig. 107. — Heterosporium gracile infecting Iris leaves. 



A, showing the infection thread piercing the epidermis ; B, showing infection thread pene- 

 trating by way of stoma ; c, conidiophores arising from thick-walled pseudoparenchymatous 

 tissue and passing through open stoma ; d, mycelium ramifying in tissues and penetrating 

 cells ; E, section parallel to surface showing both inter- and mtra-cellular mycelium. 



