394 BOTANICAL GAZETTE [DECEMBER 
I9cm.X16cm. and yielded 153 prothallia; another, measuring 
18 cm. X14 cm., yielded 134 prothallia. The third patch was the 
most yociadind being only 3cm. square, and containing 74 
prothallia. In the two larger patches there were 178 sporelings 
in all, 70 of which bore prothallia. Within the same general area 
in which the three rich patches of prothallia were found, were five 
other patches of the same general size, but which produced only 
sporelings. No effort was made to count them, but they were more 
numerous than the prothallia themselves, and were so closely 
crowded that many of them failed to produce more than the first 
set of leaves. In searching it was found to be much more profitable 
to seek patches of abundant sporelings than to wander about look- 
ing for isolated groups of them, even though these patches often 
failed to produce any prothallia in spite of the great number of 
sporelings. From this abundance of sporelings it is evident that 
not infrequently prothallia occur in even greater quantities than 
were actually secured from the richest patch found. 
RELATIONSHIP TO SPORE-BEARING PLANTS 
This investigation confirms the experiences of others who have 
found prothallia of Lycopodium, namely, that they occur most 
frequently where adult sporophytes are scarce. It seems probable 
that this situation must be explained by some difference in the 
soil. Since we know nothing of the conditions which govern the 
germination and development of Lycopodium spores, so far as the 
soil is concerned, a certain answer to the question is impossible. 
I have observed, however, that the soil in which prothallia grow 
is drier than that in which the adult sporophytes are found. This 
is especially true for the species under consideration. It is certain 
that an enormous number of spores must find their way to the soil 
beneath the cone-bearing plants, but the latter grow so thickly that 
sporelings would have little chance of survival, granting that 
prothallia had succeeded in growing. The sickly condition of 
many of the thickly growing sporelings found supports this idea. 
As a matter of fact, prothallia do occasionally occur in even 
the densest growths of adult sporophytes, and it is not improbable 
that they might be found there in quantity. The fact that investi- 
