1915] 



ATKINSON — PHYLOGENY IN THE ASCOMYCETES 



331 



Now as to the suggested relationship between the phenom- 

 enon of broad or narrow pore formation in the walls of 

 certain cells near the middle or base of the archicarp in 



certain lichens and other Ascom 

 the communications taking 



fcetes, and that shown in 

 between the carpogonium 

 and auxiliary cells (often including one or more of the 

 other procarp cells), it may be said (1) that in the red algae 

 this communication of the carpogonium (terminal procarp 

 cell) with other procarp cells when it does take place is not 

 direct, but by a roundabout method, either through a distinct 

 outgrowth from the carpogonium, or through the medium of 

 one or more auxiliary cells, or by a combination of both, to 



form the central 



(2) 



evidence of any similar round 



about method has been observed in the archicarp of the 



fungi 



The intercommunication between the middle or basal 



cells of the archicarp is always direct, and no communication 

 in the multicellular archicarp occurs by means of which either 

 a fertilized nucleus, or a sperm nucleus has been observed to 

 migrate from the terminal cell to the middle or basal cells; 

 (3) that in a number of the fungi where pore formation occurs 

 between cells of the fertile portion of the archicarp, the 

 4 ' trichogyne ' ' is either absent, or admittedly degenerate, or the 

 antheridium is absent. Examples are : Ascobolus, studied by 



Harp 



dege 



96), antheridium and trichogyne absent; Asco- 

 meus, antheridium absent, trichogyne doubtful oi 

 i; Lachnea cretea, no antheridium observed, tri 



chogyne not functional; Poly stigma rubrum, 1 trichogyne not 

 functional, from a multicellular cell at base of archicarp one 



migrates into the adjacent uninucleate archicarp 



which is 



ded as the 



ascogonium (Nienburg, '14). 



In 



of the lichens has a sperm or other nucleus been observed 



move down into the fertile part of the archicarp 



Pore 



formation in the archicarp of the Ascomycetes has no phyletic 

 relation to the fusions of auxiliary cells among themselves or 



with a short ooblastema thread or the 



It 



1 Blackman and Welsford ('12), who earlier investigated the cytology of 

 Poly stigma rubrum , are of the opinion that the "spermatia" as well as the archi- 

 carps degenerate, and that certain vegetative cells become transformed into as- 

 cogones. 



