428 BOTANICAL GAZETTE [JUNE 
was a common shrub of the locality. Aster polyphyllus was abun- 
dant and was also seen in higher ground south of the lake. 
Cladium mariscoides occurred in wet places, and several of the 
plants that have been mentioned for the low sandy borders of 
the north side of White lake.  Uvricularia cornuta occurred in 
pools. It was a small sand plain with shallow depressions and 
low dunes, bare or partially covered with vegetation, an area in 
which was to be seen a i acta with the destructive winds anda 
partial success in recovery. 
In the deep valley of the brook which joins the old outlet of 
White lake some interesting forms and associations of plants 
were found. The white cedar was the common tree in the 
springy ground. Rills fed by springs along the eastern slope 
were frequent. Two club-mosses, which are ordinarily seen 
growing in different societies, were here in company, Lycopodium 
lucidulum and L. annotinum. Such a locality is natural to the 
former, but the latter is usually a denizen of drier grounds, and 
was here seen in company with Medeola Virginica, Trientalis, 
Clintonia, and Viola Labradorica. The eastern slope was scarped 
out of the pine plain and was densely covered with white pine 
and hemlock ; the western was made by the high and fixed dunes 
which form a narrowrange between the valley and Lake Michigan, 
with a flora similar to that of the high dunes south of White 
lake. In one of the quieter places of the rills a semi-aquatic 
or floating form of Marchantia polymorpha abounded. Some 
rested on dead leaves and twigs lodged in the water. They were 
not attached by rhizoids like the ordinary terrestrial form of this 
liverwort and could be lifted out of the water by the handful 
like a Lemna or a floating Riccia. The thallus was very thin, 
especially near the base, the thinnest parts formed of the lower 
series of cells which enter into the structure of the thallus, the 
upper or lozenge-shaped layer with the stomates being absent or 
prevailing in the distal portions. At first it seemed distinct, but 
the occasional presence of the characteristic cups and gemmules, 
and the structure as a whole, showed its affinities with the 
ordinary form found on adjoining logs and earth from which it 
had spread into the water. 
