CHAPTER XVII 

 SPHAERIALES 



The Sphaeriales when first described as an order were regarded as a 

 series parallel to the Hypocreales from which they differ in their dark- 

 colored, leathery, hard or carbonaceous perithecia, always independent 

 within the stroma. Recent investigations have shown that this concep- 

 tion suits only a portion of the order, while another portion differs entirely 

 in the direction of development; thus the Sphaeriales belong to the few 

 orders of fungi whose existence is no longer justified. 



The first type in the Sphaeriales, which corresponds to the dark- 

 colored, hard Hypocreales, is designated as the Diaporthe type (Hohnel, 

 1917). In addition to lacking paraphyses, it is characterized by asci 

 which stand at unequal heights and hence entirely fill the cavities of the 

 perithecium. At maturity, their bases swell and then are held together 

 only by a gel which is easily soluble in water; hence they generally separate 

 in preparations and float away in the mounting fluid. 



Another group, differing phylogenetically, has a core of the Pseudo- 

 sphaeria type, i.e., of paraphysoids in the lower forms, and of true paraph- 

 yses in the higher forms. Still other groups, as the Coryneliaceae and 

 certain Diatrypaceae (Coronophoreae), belong to other phylogenetic 

 groups which are still vaguely defined. 



Because of this obscurity the systematic classification of the Sphaeri- 

 ales, as created by Winter (1887), Jaczewski (1894) and Lindau (1897), 

 and on which the following discussion is based, must be treated in arti- 

 ficial units, which have greatly facilitated the arrangement of an enormous 

 amount of material, but which, because they separate phylogenetically 

 related forms, make difficult the recognition of relationships. As a basis of 

 this artificial systematic classification, purely empiric characters are used, 

 as the structure and occurrence of the fructifications of the perfect forms, 

 the perithecia. Their phylogeny, their internal structure and imperfect 

 forms, however, have so far been much neglected. Hence, in only the 

 rarest cases is it possible to recognize phylogenetic relationships between 

 the different families. 



Sordariaceae. — This family includes genera with flask-shaped peri- 

 thecia with thin walls, rarely horny, without stromata (Fig. 82). The 

 members are chiefly coprophilous or otherwise saprophytic. 



As far as their development is known, it agrees with the simple Hypo- 

 creales and Plectascales. Thus in Chaetomium globosum (C. Kunzeanum) 



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