9 8 



DISCOMYCETES 



[ch. 



should be ultimately established, the curious stalked conidium of Ascobolus 

 carbonarius. 



The archicarp is of much commoner occurrence, and seems more likely 

 to be useful as a gauge of relationship. Among Discomycetes the simplest 

 type is undoubtedly that of Ascodesmis or Thelcbolus; the significant details 

 in Thelebohis are not fully known, but in Ascodesmis we have a stout, twisted 

 hypha, divided into three parts, the unicellular trichogyne, the unicellular 

 coenocytic oogonium and the multicellular stalk (fig. 56). After fertilization 



Fig. 56. Ascodesmis nigricans Van Tiegh.; sexual 

 apparatus; a. trichogyne; b. antheridium; c. 

 oogonium; (/. stalk; e. gametophytic hypha ; 

 after Claussen. 



Fig. 57. Pyronema confluens; spherical oogo- 

 nium giving rise to ascogenous hyphae; a. an- 

 theridium ; /'. trichogyne; c. oogonium ; d. as- 

 cogenous hyphae; x 1040; after Clau6sen. 



the oogonium becomes septate, so that the fertile part is multicellular and 

 the ascogenous hyphae arise from several cells. This type closely approxi- 

 mates to that in Eurotium and some other Plectascales, and there seems 

 reason to regard it as a primitive female organ among Discomycetes. 



From it may be derived the spherical oogonium of Pyronema (fig. 57) 

 which differs mainly in the fact, no doubt connected with its shape, that it 

 does not become septate after fertilization, so that the ascogenous hyphae 

 arise from one cell only. The same is true of Lachnea stercoral, which 



