336 GEORGE HARRISON SHULL 



ous submergence of nearly 4| years. The following species were 

 noted: 



Asclepias Syriaca Sium cicutaefolium 



Juncus tenuis Solidago rugosa 



Muhlenbergia diffusa Sparganizmi aridrocladum 



Phalaris sp? Syntherisma sanguinalis 



Plantago Rugelii Verbena urticaefolia 

 Polygonum sp. 



Besides these Angiosperms, the little mat-like liverwort which 

 had been noted in abundance on the pond-bed, also made its 

 appearance in the jar. 



It was decided to keep the remaining three jars for longer 

 periods but the experiment was brought to a sudden and unex- 

 pected close early in December 1912, when under a pressing need 

 for jars for other experiments, the three jars containing the sub- 

 merged seeds were mistaken for waste, notwithstanding the at- 

 tached labels which stated the character of the experiment in 

 which the jars were being used. The soil was emptied into a 

 small pile on. the grass near the laboratory, where it remained for 

 about a fortnight before I discovered what had taken place. 

 During the interval there were two sharp freezes, the minimum 

 temperature reaching — 8.3°C. on December 9, and — 7. 8°C. De- 

 cember 12. As soon as the absence of the jars was noticed a 

 search was made for the soil, which was readily identified by the 

 fact that many of the small fragments of soil still showed plainly 

 the stratification due to the method of its deposition in the bed 

 of the pond from which it had been taken. As soon as discovered, 

 the top part of the pile of soil was carefully removed and scattered 

 over the surface of sterilized soil in several seedpans. In a few 

 days numerous seedlings of Sium cicutaefolium and Juncus bufonius 

 appeared, as well as one each of Juncus tenuis, Syritherisma 

 sanguinalis and Trifolium sp. The last two could have been 

 introduced to the soil after the jars were emptied, though it will 

 be noted that one specimen of Syntherisma had appeared in the 

 jar which was emptied in 1910 in which no contamination had 

 been possible. The rest of these seedlings must have developed 

 from seeds which had been continuously submerged a fortnight 



