A TKXT-BOOK OF BOTANY. 



Single trees are treated by removing the affected branches and 

 painting over the cut ends with coal tar to prevent reinfection. 



For further details on this fungus consult: Murrill, " A Xew 

 Chestnut Disease,'' Torrcyu, Sept., 1906; Farmers' Bulletin 467, 

 U. S. Department of Agriculture; Metcalf, "Diseases of the 

 Chestnut and Other Trees. ' Trans. Mass. Hort. Soc., August, 



FIG. 32. Chestnut-blight disease, which occurs in small yellowish pustules the size 

 f.f a pin head. A, section of pustule showing perithecia; B, asci with sporidia; a, usual 

 form; 1). (<>rm ran.-Iy found; C, sporidia; D, summer spores. After Murrill. 



; l ; arlo\v, ' Fungus of the Chestnut-Tree Blight," Science, 

 May io, \()\2. 



BASIDIOMYCETES.- -The r.asidinmyceies are the most highly 

 organized of tin- l-'ungi. The imcclium consists of white branch- 

 ing threads and is usually concealed in the substratum. In the 

 cultivation of the edible mushrooms propagation is by means of 

 the mycelium, which is known commercially as "spawn." It is 

 recognized. Imwevcr, that mushrooms can not be propagated in 



