[VOL. 'I 



354 ANNALS OF THE MISSOURI BOTANICAL GARDEN 



sperm nuclei from spermatia after passing through a long 

 succession of cells constituting the trichogyne or sterile por- 

 tion of the archicarp. The trichogyne, or sterile portion of 

 the archicarp, is very long and branches into two portions, 

 one extending to either surface of the leaf. But according to 

 Nienburg ('14) sex differentiation has occurred between the 

 basal cells of the archicarp and a nucleus from the basal cell 

 migrates into the adjacent cell, which becomes the ascogonium 

 or ascogenic cell, but nuclear fusion does not take place here. 



Loss of function by the archicarp or its disappearance. — 

 A number of examples are known in which the archicarp has 

 either lost its function as a sexual organ or ascogone, or has 

 disappeared. In such cases differentiation of sex occurs in 

 special vegetative cells, sometimes by the migration of a nu- 

 cleus from certain cells into adjacent ones. In Gnomonia 

 erythrostoma, although Frank ( '86) described coiled ascogone- 

 like structures with trichogynes, and believed that the coils 

 were fertilized through the agency of the spermatia, recent 

 cytological work (Brooks, '10) on this species appears to 

 show that the tufts of hair-like structures emerging through 

 the stomates of cherry leaves, on which this species of Gno- 

 monia is parasitic, are not now connected with the coiled 

 hyphae deeper in the tissue. It appears also from the same 

 work that the ascogenous hyphae do not arise from the coils, 

 but from one or more slightly differentiated hyphae in the 

 center of each coil. 



A similar example is found in Xylaria polymorpha (Fisch, 

 '82), where an extensively coiled hypha (''Woronin's hypha") 

 occurs in the early stages of the formation of the ascocarp, 

 but later disappears and certain vegetative cells give rise to 

 the ascogenous hyphae. 



In Humaria rutilans (Fraser, '08) no archicarp or ascogone 

 coil is discernible, but certain vegetative cells function as as- 

 cogenic cells following the migration into them of nuclei from 

 adjacent cells. 



MORPHOLOGY OF THE ARCHICARP 



If the history of the Ascomycetes is correctly read from 

 the simpler and more generalized forms to the complex and 



