CHAPTER XVI 

 SAC FUNGI CONTINUED 



Suborder C. Plectasciinese. — This suborder includes fungi with a 

 well-developed mycehum on which are developed either on the surface 

 of the substratum or within it, as in the subterranean forms, closed 

 perithecia without an opening at the top. The wall of the perithecium 

 is sometimes called the peridium. The asci are developed on hyphae 

 of irregular branching, and in considerable numbers, forming irregular 

 layers of the perithecial interior. Each ascus is roimded and three- to 

 eight-spored. The spores are one- to many-ceUed. Condiospores 

 occur in a few of the forms, such as Aspergillus, Meliola and PetiicUlium. 

 Many of the fungi of this suborder are saprophytic, but some are de- 

 cidedly parasitic, as Thielavia basicola, which destroys the roots of pea 

 plants by its parasitic growth and species of the famiUes Terteziace^ 

 and Elaphomycetace^, the myceUa of which form mycorrhiza witb 

 roots of flowering plants. Economically, the suborder is interesting, 

 because it includes the common blue and green moulds and species of 

 Aspergillus used in the fermentation industries. The fruit bodies 

 of several kinds of Terfezia are used as food by the Arabs of North 

 Africa, Arabia, Syria and Mesopotamia. 



Family i. Gymnoascace.«;. — The fungi of this family are of interest, 

 because of the structure of their fruit bodies. In the genus Gymnoascus, 

 the spheric asci arise on short lateral branches of hyphae which form a 

 dense rounded mass inclosed by loosely branching hjrphae, which form 

 a basket-like inclosure of the ascus-bearing p>ortion Gymnoascus Reesii 

 is coproplulous. Some of the shorter branches of this outer envelop- 

 ment are sharp-pointed and spiny. Ctenomyces serratus, the single 

 representative of its genus, grows on deca)dng bird feathers. It 

 has branches with short hook-like extremities. The fruit body in this 

 fungus is similarly rounded and covered with hyphae that form an 

 open basket-like peridium. 



Family 2. Aspergillace^. — This family includes fourteen 

 genera, the most important of which are Aspergillus, PenitiUium and 



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