382 BOTANICAL GAZETTE - [May 
large cells composing the disk. The under surface is richly supplied 
with rhizoids. 
The gametophytes are typically monoecious. Over fifty speci- 
mens of all sizes have been examined in paraffin sections and a 
large number of others in freehand sections, and still others without 
sectioning. None has been found without old archegonia. Many, 
about 30 per cent, also bear antheridia that are still active, and 
others show the scars of antheridia that have discharged their 
sperms. Only in a few cases was it impossible to find some trace of 
G. 2.—E. laevigatum (vertical section): at left two mature antheridia; at @ 
archegonium containing young sporophyte; at 5 neck cells of functionless arche- 
gonium; X75. 
them. Antheridia, archegonia, and sporophytes often show in the 
same section. Fig. 9 shows antheridia on the left and a sporophyte 
on the right. The same thallus showed in other sections young — 
and old archegonia. Fig. 17, whose detail is shown in text fig. 2, 
shows a vertical section through the periphery of a thallus. At 
the left are two mature antheridia. At the center above at a is 
an archegonium containing in its venter a young sporophyte of 
about thirty-two cells. At 6 are the four neck cells of an old func- 
tionless archegonium. ‘Text fig. 3 shows part of a section of another 
thallus. On the left is a young antheridium in which the sperm 
