191/] 



SPESSARD—PROTHALLIA OF LYCOPODIUM 69 



by the frequent rains; later, they are covered over by the shifting 

 surface sand, and are finally conveyed to a favorable depth by the 

 percolating soil water. No experiments were made to see whether 

 this is the correct interpretation; but it was this idea which led 

 me to investigate the knolls. This observation was heeded in all 

 searches subsequent to the first successful one, and all yielded one 

 or more prothallia. 



So far as the elevation of the knolls is concerned, too much 

 importance should not be placed upon it. The fact that they are 

 elevated somewhat and exposed as they are to the air currents 

 merely causes them to be covered by leaves less frequently than 

 the lower or more wooded regions near them, and consequently 

 they offer a more receptive landing to the spores which are trans- 

 ported thither. This idea is corroborated by the fact that many 

 sporelings of L. lucidulum and L. annotinum, as well as 3 prothallia, 

 were found in the middle of a trail which is frequently used by 

 hunters. In these instances the spores were clearly trampled into 

 the soil until they found the depth required for their growth into 

 prothallia. I suspect that future observations may show that the 

 prothallia of L. annotinum and L. lucidulum require more moisture 

 for their development than the other species mentioned. The 3 

 specimens I found of these 2 species, although the surface indica- 

 tions were similar, grew in decidedly wetter places. 



In searching for prothallia, soil was removed with forceps. 

 This method was not very satisfactory, however, and 4 of the 

 prothallia were broken or pierced by the forceps before they were 

 seen. It would be better to remove the soil to a depth of 10 cm. 

 and wash it through a coffee sieve. This would not only avoid 

 the danger of damaging prothallia, but would increase the proba- 

 bility of finding young stages. The specimens grew at depths 

 varying between 1 and 7 cm. The species growing nearest the 

 surface is L. lucidulum; the one growing deepest is L. obscurum. 

 In one hole 2 kinds, L. clavatum and L. obscurum, were seen within 

 2 cm. of each other. 



The prothallia of L. clavatum and L. annotinum grow with the 

 wrinkled side toward the surface, and the primary tubercle pointed 

 downward; that of L. lucidulum grows erect and the sporeling 



