150 Rhodora [July 



else in the state combined. Anetithobium pusiilum, Peck — a fourth 

 plant new to the state — was found to be covering many of these 

 trees. The party returned happy botanically although somewhat 

 uncomfortable as the result of a persistent and penetrating rain. 



The retrospective view of an excursion of this sort often reveals 

 vistas of thought and speculation which are sometimes of consider- 

 able interest. In this particular case at least two such have been 

 opened to the writer. 



First, it is impossible to believe that this section of the state could 

 ever have been visited by such well known sharp-eyed older Rhode 

 Island collectors as S. T. Olney, G. Thurber, J. W. Bailey, A. L. 

 Calder, G. Hunt and J. W. Congdon, or some of these plants would 

 long ago have been added to the known flora of our state. 



Second, the speculation as to the origin and survival of such 

 unique plant formations is of extreme interest. The writer has not 

 fully satisfied himself as to the origin of these characteristically 

 northern plants at this station, but probably it is not unlike that of 

 other plants growing in similar situations elsewhere. The condi- 

 tions which maintain them are, on the other hand, apparently quite 

 evident. All the bogs are of the floating type, though anchored by 

 at least a few roots or stems so that they do not drift about over the 

 surface of the pond. Beneath the film of floating vegetation there 

 is often twelve or more feet of water, as we learned by measuring 

 through some of the numerous and treacherous openings in the float- 

 ing mass. In the winter the ice forms beneath as well as through 

 this comparatively thin layer of loosely entangled stems and peat 

 moss. As the warm weather approaches in the spring the ice in the 

 open pond is readily melted ; not so with that in and under the 

 bogs. Shielded from tlie sun's rays by the mass of stems and moss 

 it melts but slowly and lingers long into the spring. At the date of 

 our visit (igth of May) the ice at the depth of eight inches or a foot 

 below the upper surface was still, in many places, too thick for us to 

 break even by jumping upon it. In the more exposed spots it had 

 entirely melted and at intermediate places we succeeded in breaking 

 it where it measured more than an inch in thickness. It will thus 

 be seen that many of the plants, while yet in bloom, had the lower 

 part of the stems and roots at least partially encased in ice — a truly 

 boreal condition of affairs and one which readily accounts for such 

 an abundance of these northern plants at this station. 

 Providence, Rhode Island. 



