PLATE IV. 

 Cucumber Diseases. — Hazel Fungus. 

 Figs. 25-26. Leaf blight (Cladosporium rMcumerhium Ell. & Arth.). 

 Fig 25. Epidermis of lower surface of leaf, with stomata, St., showing mycelium, m, 



and hyphal knots, giving rise to spore threads, sp., detached spores of the 



fungus. 

 Fig. 26. Mycelium, m, and hyphal knot, a, giving rise to spore threads, the latter with. 



highly developed spore chains. 

 Figs. 27-29. Leaf glaze {Acremonium sp.). 

 Fig. 27. Mycelium giving rise to numerous spore threads. 

 Fig. 28. Ripe spores, fallen from the threads. 

 Fig. 29. Spores germinating in water. 



Figs. 30-33. Hazel fungus {Gryptosporella anomala (Pt.) Sacc). 

 Fig. 30. A piece of a branch of hazel, showing the depressed region occupied by the 



fungus, a, and fourteen of its compound spore fruits. Natural size. 

 Fig. 31. A vertical section, showing five spore cavities, through a spore fruit lying at the 



margin of the infested area, showing the wood of the branch, w, the inner 



bark, a, in normal condition at the right and destroyed by the fungus at the 



left, and the outer bark, o. X 3. 

 Fig. 32. An ascus with its eight spores. X 9-10. 

 Fig. 33. Three ripe spores. X 940. 



PLATE V. 



The Black Knot of Plum and Chebrt {Plowrightia morbosa (Sz.) Sacc). 



Three young branches from the wild black cherry {P^-unus acrotina), taken about May 1, 

 showing two stages of the knot. In the large knot, o, the development and escape of the 

 winter spores has just been completed, and its activity is past. The three small knots, a, 

 just bursting the bark, are a year younger than the large one, and are about to begin the 

 production of their summer spores. Natural size. From a photograph. 



