COLLEMA. 



127 



gyne are smaller in diameter than those of the ascogonium, and their 

 number varies in the species examined from six to twenty-four. A 

 sharp demarkation between trichogyne and ascogonium does not exist. 



The end of the trichogyne which 

 projects above the surface of the 

 thallus is generally short and cylin- 

 drical or flask-shaped. In rare cases 

 it ends in two short and nearly equal 

 branches. The free surface of this 

 end cell is covered by a viscid sub- 

 stance which facilitates the adherence 

 of the spermatia that escape in large 

 numbers during moist weather from 

 the flask-shaped male organs, the 

 spermagonia. 



Baur ('98), who studied Collcma 

 crispum, confirms Stahl's observa- 

 tions, and gives additional informa- 

 tion concerning details of cell struc- 

 ture. The terminal cell of the trich- 

 ogyne in Collema crispum, which 

 projects above the surface of the 

 thallus, is much larger than the other 

 cells of this organ, being longer, 

 somewhat swollen at the middle, and 

 terminating in a point (Fig. 50, B). 

 It is also provided with a viscid 

 coating. 



Each cell of the entire carpogo- 

 nium possesses a nucleus of the typi- 

 cal structure. The transverse walls 

 between the cells are not broken 

 down, though each reveals a small 

 pit, such as is present in the trans- 

 verse septa of vegetative hyphae. 

 In four cases Baur found empty 

 spermatia attached to the end of the trichogyne, whose cells showed 

 the same signs of degeneration described by Stahl. The cells in the 

 upper part were collapsed, the cross- walls much swollen, and no nuclei 

 could be seen in them. The septa between the lower cells of the 

 trichogyne were clearly broken down. Each cell of the ascogonium 

 contains at first one nucleus, and since each gives rise to ascogenous 



FIG. 50. Carpogonium of Collema crispum. 

 (After Baur.) 



A, mature Carpogonium ; trichogyne ends in 



large receptive cell which projects above 

 surface of thallus. 



B, receptive cell with which a spermatium 



has fused. 



