BRYOPHYTES—MUSCI 
239 
in eosin, or in Magdala red and anilin blue. Mount in Venetian 
turpentine. 
Antheridia. -It is easy to find material for a study of antheridia, 
because, in so many cases, the antheridial plants can be detected at 
once without even a 
pocket lens. Funaria, 
with its bunch of anther¬ 
idia as large as a 
pinhead, is extremely 
common everywhere. 
Spring is the best time 
to collect it, but it is 
found fruiting in the 
autumn and sometimes 
in summer; besides, it 
is easily kept in the 
greenhouse, where it 
may fruit at any time. 
Bryum roseum has a 
large cluster of anther¬ 
idia surrounded by ra¬ 
diating leaves, making 
it easy to recognize. 
Other species of Bryum 
and species of Mnium, 
like M. cuspidatum , 
make good sections. 
Polytrichum has a large 
cluster of antheridia 
surrounded by reddish 
leaves, so that the whole 
is sometimes called the 
moss “flower.” In fix¬ 
ing this or the closely 
related Atrichum ( Ca- 
tharinea), cut a small slab from two Sides, so as to leave a flat piece 
to cut for longitudinal sections. This trimming will greatly facilitate 
fixing and infiltration. A single antheridial plant of Poly trichum 
often furnishes a fairly complete series of stages in the development 
Fig. 73 .—Mnium cuspidatum: A, nearly mature antheri- 
dium in the center, with a young archegonium at the right, 
and at the left a still younger stage which may develop into 
either an antheridium or an archegonium; B, a nearly mature 
archegonium with a young archegonium at the right. Fixed 
in formatin, acetic alcohol (formalin 10 c.c., acetic acid 5 c.c., 
50 per cent alcohol, 100 c.c.) and stained in safranin, gentian- 
violet, orange. X240. 
