DISCOMYCETES 



[CH. 



n8 



or four cells, which diminish gradually in diameter and which he terms 



a trichogyne. 



In Ascobolus immersus the mycelium consists of multmucleate cells, the 

 archicarp is larger than that of A. Winteri and contains some twenty 

 divisions, it is otherwise very similar. The cells contain numerous large 

 nuclei and pores develop between them ; the ascogenous hyphae arise from 

 a single cell. Ramlow observed nuclear fusions in the central cell of the 

 archicarp, but referred them to bad fixation. His explanation may be 



adequate here, but it does not 

 invalidate the observations of 

 authors who have recorded 

 fusions in properly fixed ma- 

 terial. In archicarps which he 

 held to be satisfactorily fixed 

 Ramlow saw pairing of nuclei 

 in the ascogenous cell, and 

 records that they wandered in 

 pairs into the ascogenous hy- 

 phae (fig. 78), not fusing till 

 the asci were about to develop. 

 In the divisions of the ascus 

 the number of chromosomes is stated by Ramlow to be sixteen through- 

 out, but he does not figure the essential third anaphase. 



Ascobolus carbonarius occurs on burnt ground among charcoal. The 

 ascocarp is scurfy (furfuraceous), and greenish, 'or later brownish in colour. 

 Numerous conidia are formed on the mycelium, and, according to Dodge, 

 it is from a conidium, germinating while still attached to its stalk, that the 

 archicarp is produced. It consists of a multicellular stalk, a fertile portion 

 which contains twenty to forty cells arranged in a loose irregular spiral, and 



a terminal trichogyne more or 

 less coiled, tapering towards 

 the end, and including some 

 ten to twenty cells. The apex 

 of this trichogyne is found to 

 wrap itself tightly round a 

 second conidium, attached, 

 like the first, to its stalk (fig. 

 79). This conidium is re- 

 garded by Dodge as the an- 

 theridium, but no cytological 

 details have as yet been published. 



Ascophanus carneus is a somewhat variable species. Its red, pink, or 



Fig. 78. Ascobolus immersus Pers. ; archicarps showing 

 paired nuclei, x 1000; after Ramlow. 



Fig. 79. Ascobolus carbonarius Karst. ; archicarp, x 280 ; 

 after Dodge. 



