46 MISSOURI BOTANICAL GARDEN. 
serpyllifolia, is found overrunning all the areas described 
above. Gaultheria procumbens, Sarracenia purpurea 
and Drosera rotundifolia are likewise common but not 
confined to any particular zone. 
Coming into the open water, Polygonum Hartwrightii, 
Phragmites communis, Typha latifolia and Nuphar advena 
complete the list of common and typical forms. 
In a peat bog in the vicinity of Mount Katahdin, Maine 
(Plate 6), the filling up of the depression had progressed 
farther and there was little open water remaining. 
Although this area is 2,600 feet above tide water, there 
is found a considerable similarity between the species rep- 
resented there and those in the northern Michigan swamp. 
Larix Americana is very scarce in the Maine region, though 
the lumbermen say that a number of years ago it was 
plentiful but was killed off by ‘* borers.’’ In any case the 
dominant tree now found about this swamp is the black 
spruce, Picea nigra. 
These trees are very small upon the east side, larger on 
the north, where are found a number of trees of Thuya 
occidentalis also, and largest upon the west side where 
Pyrus Americana is associated with the spruce. It is 
practically the only tree on the south side. 
Among the shrubs characterizing the Northern Michigan 
area, there were found here Cassandra calyculata, Nemo- 
panthes fascicularis, Kalmia glauca and Pyrus arbutifolia. 
Vaccinium Canadense is found in the neighboring thickets ; 
and in the bog itself are found V. Oxycoccus, V. uligino- 
sum and V. Vitis-Idaea. 
The strictly water forms, Potentilla palustris, Menyanthes 
trifoliata, Polygonum Hartwrightii, Phragmites communis 
and Typha latifolia were not found in the Maine swamp: 
as has been already stated there is little open water left. 
In the wettest places species of Sphagnum, Scheuchzeria 
palustris, Drosera rotundifolia and Sarracenia purpurea are 
the typical plants. Osmunda cinnamomea is a character- 
