1915] 



ATKINSON — PHYLOGENY IN THE ASCOMYCETES 



333 



case has fertilization by a free sperm been determined, and 

 forms with a multiseptate "trichogyne," or oogonium, the i 

 called spermatia, or antheridia, do not, so far as we know, pi 

 the usual role in fertilization, not even a modified role by 

 ciation with the oogonial nuclei. 



2. The individual nuclei of the ooblastema filaments are of 

 the usual diploid character, and there is no fusion of these 

 nuclei prior to the formation of the carpospores. The indi- 

 vidual nuclei of the ascogenous threads, or ascogenic cells, are 

 probably haploid in character, and sooner or later form the 



d synk 



an association of two 



lent to a diploid 



nuclei, together 



Fusion of the paired 



takes place before the formation of the ascospores. 



3. It has been suggested that the complex processes in the 

 extensive migration, branching and fusions of the ooblastema 

 filaments with auxiliary cells as is known to occur in the 



Crypt 



(as in Dud 



Cruo 



Gloe 



phonia, etc.), may furnish still more important evidence of 

 the ancestry of the Ascomycetes than that suggested in the 

 fusions of procarp and auxiliary cells on the one hand, and 



) fusions of the 



archicarp cells on the other (Dodge 



Th 



ooblastema filaments with auxiliary cells and the production 

 of sporogenous threads from the central cells thus formed, 

 are supposed to be represented by the fusions which are known 

 to occur between the ultimate and antepenult cells of the ascus 

 hook prior to the formation of additional asci. The processes 

 in both groups result in the multiplication of spore origins 

 and consequently in an increase; in spore output. Perhaps the 

 nearest analogue to the process in the Ascomycetes which re- 

 sults in the formation of the ascus with its four to eight spores, 

 is found in Cruoriopsis, where one or two spore chains of two 

 to four spores each are produced as a result ( Schmitz, 79, '83 ; 

 Oltmanns, '04). The theory of " second sexual fusions" in 

 the red algae was founded on the discovery of these fusions of 

 the ooblastema filaments with auxiliarv cells, since it was an re- 



posed that a fusion 



rred between the nucleus of the 



ooblastema filament (derived from the diploid nucleus of the 

 fertilized ess) and the nucleus of the vearetative auxiliarv cell 



