The Origin and Development of the Apothecium in 
Collema pulposum (Bernh.) Ach. 
By 
Freda M. Baclimann. 
With plates XXX to XXXVI. 
In their studies of various lichens, Stahl, Borzi, Sturgis, Dar- 
bishire and Baur fonnd the spermatia to function as male cells; yet in 
spite of the positive evidence supplied by these authors, fully as many 
others have eontinually denied the sexual nature of the spermatia. Those 
who have chosen to regard the cells in question in some of the pyrenomy- 
cetes and in the rusts as male cells, have based their condusions either 
largely or entirely on the very apparent cytological resemblance to male 
cells in other plants and to the complete inability, or much reduced power 
of these cells to germinate. Beside the question as to the nature of the 
spermatia, there is also the interesting problem of nuclear behavior in 
the fertilization of such a multicellular female organ as is commonly 
found in many pyrenomycetes and the lichens. With these questions 
in mind and with a view to throwing light on the problems involved, 
I have undertaken further studies on the lichens, among which the Col- 
lemaceae have thus far proved most favorable for my work. 
In a former paper (1) as a necessary introduction to a morphological 
desc-ription of the reproductive structures in Collema pulposum, I gave 
a very short historical sketch of some of the more important literature 
bearing on the development of the apothecium in lichens. In the present 
paper I sliall attempt to give a more complete review of the work done 
up to the present time, also a more complete account of the results of 
my own studies. 
Archiv f. Zellforschung. X. 
25 
