298 TEXT-BOOK OF FUNGI 



through which the spores escape from the perithecium at 

 maturity, appears as a very narrow slit. 



Appearing as minute black specks on wood, branches, 

 and herbaceous stems. Mostly saprophytes. 



Distribution general. 



Hysterieae 



Perithecia elongate, simple or branched, sometimes with 

 several radiating arms, sometimes vertical, like a mussel- 

 shell standing on its edge. Allied to Lophiostomaceae, 

 differing mainly in the longer ostiolum, which runs the 

 entire length of the perithecium as a slit or groove, 

 usually bounded by thickened ridges or lips. This group 

 was until recently included in the Discomycetes, but the 

 coriaceous or carbonaceous perithecia, and often coloured 

 and multiseptate spores, 'are considered by Saccardo to 

 indicate a closer affinity to the Pyrenomycetes. 



The majority are saprophytes, growing on wood or bark. 

 A few are parasitic on living leaves and stems. 



So far as at present known, most abundant in the 

 northern hemisphere. 



Tuberaceae 



Ascophore subterranean, or- in some species only imper- 

 fectly buried or growing amongst decaying leaves. More 

 or less globose or irregularly nodulose, firm ; the wall of 

 the ascophore is sometimes continuous, in other species 

 possessing an opening or perforation. The gleba is either 

 compact or lacunose. In some genera the asci are 

 cylindrical, in others nearly globose. The spores are often 

 very large, having the exospore covered with warts, spines, 



