374 
Freda M. Bachmann 
the empty spermogonium becomes the apothecium. The ascogones, 
which are more or less winding but not spiral, are in the base of the sper- 
mogonium, and the trichogynes grow from here to the surface of the 
thallus around the spermogonium. As in Collema, the limit of trichogyne 
and aseogone is sharply defined. The thickening of the cross walls is 
confined to tliat part of the carpogone which is outside of the base of 
the spermogonium. The changes in the trichogyne cross walls begin at 
the distal end of this structure, which to Stahl suggests that the thicken- 
ing is due to the Chemical effects of substances moving througli the cells 
and downward — evidence of the sexuality of these species. The spermatia 
are mature and are extruded at about the time the trichogynes are mature, 
so that the latter are always found with numerous spermatia attached. 
After the spermatia are extruded, the asci and paraphyses grow upward 
and fill the old spermogonium. In Collema there is but one carpogone 
for each apothecium, in Pkysma there are always more than one. The 
size of the apothecium is not correspondingly larger in the latter as might 
be expected. In Collema the exciple and hypothecium arise after fertili- 
zation. That the spermatia are the male cells of lichens and that we 
have in spermatia, trichogyne and carpogone a genuine functional sexual 
apparatus seems to have been conclusively demonstrated by Stahl's 
work, in spite of the attempts of Brefeld, Möller and others who see 
no evidence of sexuality in the ascomycetes to weaken the evidence. 
Four years after the appearance of Stahl’s paper, Krabbe (58) 
described a vegetative origin for the fruit body in several lichens. Ac- 
cording to Krabbe’s observations the ascogenous hypliae in several 
species of lichens of different genera originale in vegetative hyphae but 
become differentiated so tliat asci are borne at or near the ends. There 
is no difference in origin between the hyphae giving rise to the asci and 
to those giving rise to the paraphyses, although the ascogenous hyphae 
are not developed until the fonnation of paraphyses is begun. In Splnj- 
ridium carneum what Krabbe believes are ascogenous hyphae are formed 
but no asci are produced. He suggests tliat this species reproduces only 
by means of soredia. Spermogonia are never or at least seldom produced. 
In Cladonia papillaria Ehr. a bunch of paraphyses may grow upward 
from the center of the apothecium and thus form a secondary fruit body 
from which again in the same way a third may be formed. The hymenium 
of the primary apothecium ceases to develop and the paraphyses branch 
and form a weft of tissue which covers the asci. With the exception 
of a few asci that may or may not be carried upward by the growth of 
the paraphyses to form the secondary apothecium, the tissue of the youug 
