1922] SPESSARD—LYCOPODIUM 401 
and assimilative in function, in its upper portion, while its lower 
portion is employed for the storage of food material. The starch 
grains are compound. While they occur most abundantly in the 
lower half of the upper set of tissues, very frequently they are found 
also in the cells immediately below the epidermis, in the venter 
of the archegonium and the cells of the fungus regions (fig. 64). 
Approximately the lower half of the prothallium is inhabited by 
the endophytic fungus. This will be described later. 
The meristematic tissue (figs. 51, 52) lies at the apical end of 
the prothallium in a depression between the two groups of tissues 
just named. A single apical cell is probably not present. Growth 
is apparently brought about by periclinal and anticlinal division 
of a small number of cells which form a meristematic plate between 
the youngest portions of the upper and lower sets of tissues. The 
mitotic figures of fig. 51 show that division continues in cells which 
lie at a considerable depth. The lobed-like mass of tissue which 
bends downward over the apical region and which bears the pri- 
mordia and older cells of the sex organs is caused by this division 
of the interior cells, as well as by the rapid division of the more 
: superficial ones. The cells of the meristematic plate, from which 
are cut off immediately the vegetative and reproductive primordia, 
are filled with dense protoplasm and numerous oil drops (fig. 53). 
_ Rhizoids.are very abundant, and are simple elongations of 
epidermal cells on the lower side. No case was observed in which 
a rhizoid was cut off by a cross wall. 
SEX ORGANS 
The prothallia are monoecious. The sex organs appear in 
acropetal succession (fig. 51), the older ones being located (fig. 50) 
in the tissue lying above the primary tubercle. Both antheridia 
(figs. 54-58, 62) and archegonia (figs. 42-47) develop by the usual 
stages known for the genus. The largest number of canal cells - 
found was four. A double row of these was not observed. The 
ventral canal cell is very much flattened at maturity. The egg 
is slightly oval at maturity, with the long axis perpendicular to 
the canal. It almost completely fills the venter. The neck of 
the archegonium is short, and the venter lies completely below the 
