248 PHYLUM VIII. BRYOPHYTA 
Laboratory Studies. (a) Look for Riccias on the wet 
ground by the sides of ponds and slow streams from midsummer 
to fall. Make careful vertical sections for structure of the 
gametophyte, at the same time looking for the sexual organs 
and the imbedded sporophyte. 
(b) Study Anthoceros for gametophyte, and cylindrical spor- 
ophytes. In the latter find stomata, spores and simple elaters. 
Anthoceros may be obtained from the South (Gulf states) for 
study in early spring. 
(c) Collect specimens of the Great Liverwort (Marchantia) 
which may be found in fruit in midsummer. Note that one 
plant produces the antheridial branches, which have flat disks, 
and another produces the archegonial branches, which have 
lobed disks (‘‘receptacles’’). Note the cups, with contained 
brood masses (gemmae). 
(d) Examine the upper surface of a plant with a low power 
of the microscope, and note the round “stomata.” Next strip 
off some of the epidermis, mount in alcohol, and study with a 
high power. 
(e) Make longitudinal sections of the plant through its 
thickened. central rib, and observe the elongated cells, with 
foreshadow fibro-vascular bundles. 
(f) Make vertical sections of the antheridial disk, mount in 
water, and study the antherids. By repeated trials sperms 
also may be seen. 
(g) Make similar sections of the archegonial disk, and study 
archegones. By taking older specimens the sporophytes, 
spores, and elaters may be studied. For the latter, mount in 
alcohol and afterward add a little potassium hydrate. 
(h) Examine the bark of trees for small brownish Scale 
mosses. Mounta bit of one in alcohol, afterward adding potas- 
sium hydrate, and study for structure of the gametophyte. 
In the spring the minute splitting spore cases may readily be 
found. 
. Crass MUSCI. Mossgs 
437. The gametophyte in this class is a leafy multi- 
lateral stem, rarely bilateral. It is fixed to the soil or 
other support by root-hairs (rhizoids) which grow out 
from the sides of the stem. The leaves are usually ~ 
