1922] WATERMAN—PLANT COMMUNITIES 13 
aquatic communities, from those which are nearly all floating 
aquatics to the grass meadow or the swamp shrub thicket. There 
are few characterized by a true bog mat, but many contain charac- 
teristic bog plants and shrubs. The grass meadows vary in size 
from a few yards in diameter to one too yards wide, and one-half 
to three-quarters of a mile long; while two others of equal length 
are 200-300 yards wide (fig. 11). These are usually bordered by a 
narrow shrub zone between the sand ridge and the meadow, includ- 
ing Alnus incana, Pyrus arbutifolia, Rosa carolina, and Cornus stol- 
Fic. 5.—Chamaedaphne meadow with Picea Mariana and Larix laricina 
onifera. With the grasses and sedges in the smaller meadows are 
found also Hypericum virginicum and Spiraea salicifolia, while 
occasional specimens of aquatics occur, as Jris and Sagitiaria. In 
one case a remarkable growth of Lobelia cardinalis covered one acre 
of meadow with its scarlet flowers. 
The bogs are generally found at or near the border of a lake or 
river, and are of two general types, one an ericad heath, the other 
a tamarack thicket. The heath type has a more or less continuous 
cover of sphagnum with its usual accompaniments: Sarracenia 
purpurea, Vaccinium macrocarpon, Drosera rotundifolia, Menyanthes 
