Ill] PLECTASCALES 77 



the spores lie free amongst the vegetative hyphae. This mature stage, in 

 which there is no trace of asci, caused Onygena to be variously classified 

 with the Myxomycetes and with the Lycoperdaceae before its true position 

 was discovered. There is no evidence of the existence of sexual organs. 



ONYGENACEAE : BIBLIOGRAPHY 



1899 Ward, H. Marshall. Onygena equitia Willd. A Horn-destroying Fungus. Phil. 



Trans. B. cxci, p. 269. 

 1917 Brierley, W. B. Spore Germination in Onygena equina, Willd. Ann. Bot. xxxi, 



p. 17. 



Elaphomycetaceae and Terfeziaceae 



In the next two families, Elaphomycetaceae and Terfeziaceae, the fruit 

 is subterranean. The species differ from the other hypogeal Ascomycetes, 

 the Tuberales, with which they are still sometimes classified, and resemble 

 the subaerial Plectascales in the irregular arrangement of their asci, which 

 are scattered or grouped in nests surrounded by sterile branches (fig. 37). The 

 gleba or central complex of hyphae is not at any stage of development in 

 communication with the exterior. 



In the Elaphomycetaceae the ascocarp is surrounded by a thick yellow 

 or brown peridium, the asci are subglobose and the gleba breaks up at 

 maturity into a powdery mass of spores. The only genus is' Elaphomyces. 

 The mycelium of certain species develops in relation to the roots oi Piims 

 and other conifers, and the ascocarp is often parasitized by species of the 

 pyrenomycetous fungus Cordyceps. E. gramdatiis, the commonest British 

 species, is the host of C. capitata, and E. variegatus of C. ophioglossoides 

 (fig. no). 



In the Terfeziaceae (figs. 36, 37) the peridium is much less distinct, and 



Fig. 36. Terfezia olbiensis Tul. ; section of fructification ; after Tulasne. 



in some cases is represented merely by an ascus-free region around the 

 periphery of the fruit. Moreover the spores do not, as in the Elaphomy- 

 cetaceae, form a powdery mass at maturity. 



