198 THE ASCOMYCETES 



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104, 1936. 

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Arten," Botan. Z., <Ji: 111-158, 1903. 

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3 ser., 20:5-56, 1853. 

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alterer Sclerotien von Claviceps purpurea,'' Z. Pfianzenk., 76:129-131, 



1906. 



Sphaeriales 



The Sphaeriales, the largest order of Pyrenomycetes, is vari- 

 ously estimated to include between 6000 and 10,000 species, 

 mostly saprophytic, but many parasitic, especially on seed plants. 

 Its members are distinguished by their dark membranaceous, 

 corky, or carbonaceous perithecia, which either stand singly and 

 free or are variously aggregated and embedded in the substrata 

 or in stromata. Of this vast assemblage only a relatively small 

 number have been carefully studied; hence adequate bases for 

 classification are lacking, and a purely artificial system must 

 therefore be employed. Lindau, in Engler and PrantFs Die na- 

 tiirlichen FflanzenjavnUen, recognizes 18 families, and Martin 

 (1936) recognizes 12 famiUes, both employing similar character- 

 istics throughout. Shape, septation, and color of spores are em- 

 ployed in distinguishing genera; species, unfortunately, are too 

 commonly separated on the basis of host and substrate relation- 

 ship. 



The families of Sphaeriales considered in this book may be 

 distinguished as follows: 



a. Perithecia free or nearlv so b 



b. Wall membranaceous c 



c. Upper portion of perithecium having long, straight, or coiled 

 and branched hairs Chaetomiaceae 



c. Ostiolar region lacking hairs, mainly, dung inhabiting 



Fimetariaceae (Sordariaceae) 

 b. Wall leather>^ or carbonaceous d 



d. Perithecia with papillate ostiole Sphaeriaceae 

 d. Perithecia with beak-like ostiolar region Ceratostomataceae 



a. Perithecia partly embedded in substratum or in stroma e 



