424 
Freda M. Bachmann 
develops independentlv of the spermatia in “many” cases or perliaps 
in any case. Certainly mucli more study is needed on tliese forms. As 
to the inability of tliese spermatia to germinate, Blackman (9) has pointed 
out that “a complete absenee of power of vegetative development is not 
a necessary cliaracter of male cells, as is shown by the well-known cases 
of the potential gametes of some algae which can develop either sexually 
or asexually”. Möller’s results as to germination may or may not be 
correct, but the conditions in Collema pulposum certainly furnish a final 
and complete demonstration that the spermatia of lichens are male gametes 
and not asexual conidia. 
In my former paper (1) I have emphasized the greater resemblance 
of Collema pulposum , as compared witli other lichens, to Pyronema in 
respec-t of the greater activity of the trichogyne, the manner in which 
the trichogyne grows toward and coils about a spermatium, and the 
reduced number and greater fixity of the spermatia, which are thus more 
like antheridia. I called attention to the very great similarity of the 
reproductive structures of C. pulposum to tliose of some of the Laboul- 
beniaceae as described by Thaxter (18, 19). I have also discussed the 
old question of the relation of the ascomycetes to the red algae in the 
light of my present studies, pointing out that in the number and nature 
of its spermatia and in the manner in which they are borne, Collema 
pulposum forms about the most perfect conceivable connecting link 
between the aquatic red algae with many non-motile male cells which 
are, however, set free, and such terrestrial ascomycetes as Pyronema and 
the mildews where the male cells are reduced in number to one or two 
which remain permanently attached. 
I wish again to ac-knowledge my indebtedness to Prof. R. A. Harper 
at whose Suggestion this study was begun for his helpful advice and criti- 
cism wliile mucli of the work was in progress, and to Prof. C. E. Allen 
for various helpful suggestions and the eritieal reading of the manuscript. 
Madison, Wisconsin, Aug. 1. 1912. 
