Minnesota Plant Diseases. xv 



Fig. 38. Two ways in which wood is destroyed by wood-rot fungi. 



Highly magnified. After Hartig 86 



Fig. 39. A good example of an epidemic. Potato-blight has within 

 a week entirely destroyed the potato plants in this field. 



After Clinton 99 



Fig. 40. An epidemic of mildew on ciicumbers checked by spraying. 



After F. C. Stewart loi 



Fig. 41. A lowly algal fungus. Highly magnified. After Schroeter. . 105 

 Fig. 42. Water and fish molds. Highly magnified. After various 



authors 106 



Fig. 43. Sewer-pipe fungi. Highly magnified. After Pringsheim. .. . 108 



Fig. 44. Downy mildews. Highly magnified. After De Bary IC9 



Fig. 45. A downy mildew with the aspect of a white rust. Original. . iii 



Fig. 46. A black mold. Highly magnified. After Zopf 113 



Fig. 47. An insect mold. Highly magnified. After Brefeld I IS 



Fig. 48. Yeast fungus cells. Highly magnified. After Rees 118 



Fig. 49. Plum-pocket fungus and loose-weft fungus. Highly magni- 

 fied. After De Bary and Sachs 121 



Fig. so. A powdery mildew on common plantain leaf. Original 124 



Fig. si. The fruiting body of the powdery mildew of black haw, show- 

 ing the appendages. Highly magnified. Microphoto- 



graph by E. W. D. Holway 125 



Fig. 52. The fruiting body of the powdery mildew of willows, show- 

 ing the appendages and spore-sacs. Highly magnified. 



Microphotograph by E. W. D. Holway 126 



Fig. S3- Ergots of grasses. Original 127 



Fig. 54. Ergot fungus on canary grass. Original 128 



Fic. SS- Fruiting bodies and spores of the ergot fungus. Variously 



magnified. After Tulasne and Brefeld ' 130 



Fig. 56. A caterpillar fungus. Original 131 



Fig. 57. A strangling fungus on grass leaves and stems. Original. ... 132 



