1922] SPESSARD—LYCOPODIUM 403 
on plants where primordia of sex organs are apparently alike in 
position, suggests that we may be dealing with one of the primitive 
stages of sex organ development. Ho.Lrerty (2) found the same 
indifferent situation in Mnium cuspidatum. Miss Lyon brought 
together considerable information on several genera of pteridophytes 
regarding the condition in abnormal archegonia. A longitudinal 
section is best for the study of sex organs. 
Only the first division in the development of the prothallia 
from the spore was observed. Fig. 1 illustrates the single specimen 
which was found in field material. 
Lycopodium obscurum dendroideum 
The prothallia of this species were most difficult to find. The 
sporelings have an appearance so much like those of L. complanatum 
that a certain abnormally growing prothallium of the latter species 
was described in my first paper (4) as that of L. obscurum. This 
error was corrected as soon as discovered (5). A total of thirty- 
seven prothallia were found. Twelve were dug up in a patch 2 
feet square near the locality described for L. lucidulum, and very 
near to a juniper bush. The others were found near Mid-Island 
Point, Michigan. The exact spot lies just behind a row of cottages, 
about 300 yards from Lake Superior and in an alder clump between 
the lake and the marsh to the east of it. This spot was visited 
first in July and later in August of 1917. It was very dry at this 
time, but is probably water-logged for at least two months of the 
year. Twenty-five prothallia of LZ. obscurum, fifteen of L. com- 
planatum, and six of an undetermined variety of L. clavatum were 
found in an area not more than ro feet square. 
The soil in the first locality contained very little humus in the 
sand. A species of grass and Polytrichum grew about the spot, 
which was fully exposed to the sun, and no leaf mold was present. 
e sand was yellowish a short distance below the surface, and 
rather compact. The spot rests on a ridge about 15 feet higher 
than the surrounding land. The lake bed once covered this point, 
and it is probably an old sand bar. 
The soil of the second locality could hardly offer,a more contrast- 
ing condition as to physical appearance. The subsoil of course 
