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ASCOMYCETES. 



Scleroderris. 



A black stroma is formed in the bark of twigs attacked 

 by this fungus, and thence the apothecia break out in great 

 numbers, at first as closed spheres, later as stalked open 

 cups with finely lobed rims. The asci are cylindrical or club- 



Fio. 134. — HcUroderris fiUiginosa on living twig of Salix alba. 

 A, Three apothecia, two in section, the third seen from above, 

 showing the cross-like fissure. B, Sections of diseased branches, 

 whose growth has been arrested in the shaded parts ; on the 

 dead bark apothecia are present. (', Asci, spores and paraphyses. 

 (v. Tubeiif del.) 



Fic. 183.- -Scleroderris full- 

 qiHosa on living twig of 

 Salix Caprea. (v. Tnbeuf 

 del.) 



shaped, and contain eight colourless spores which are club- 

 shaped, needle-shaped, or thread-like, and divided by septa into 

 four to eight cells. The pores of the asci are coloured blue 

 by iodine. The paraphyses are thread-like. 



