I0o BOTANICAL GAZETTE [AUGUST 
competition may therefore determine some of its minor features, 
but to these I gave no attention, 
The turf reaches its climax in the open swales like those shown 
by fig. ro. In the woods it disappears, as will be noted under the 
next section; but towards the lower levels, especially towards the 
pools of standing water, it gives way gradually, by definite steps, 
to an assemblage cf true swamp plants. The very first of these 
to appear in the lcwer places in the swales is always the common 
blue flag, Iris versicolor, and characteristic scattered clumrs of 
this plant may be seen in the fcreground in fig. 11, in the distance 
farshy swale, looking south; in the center a permanent pool with 
margin ‘saibea’ oN cattle; behind it are cat-tails and rushes, and back of them a thicket 
of poplar; on both right and left is sweet gale, and in the foreground is the blue flag- 
on the swale in jig. 8, and cn the left margin of the swale in jig. 12 
Next follows always the sweet gale, Myrica Gale, and after that 
low bushes of the balsam poplar, Populus balsamijfera, a plant which 
forms very dense thickets and grows larger as the situation is more 
sheltered. Finally the pools of standing water are reached, and 
on their margin cccur cat-tails, rushes, and mare’s tail, Hippuris 
vulgaris, with some other forms which I have not attempted. esp& 
cially to study. The plants may be variously combined according 
to local circumstances, but a very typical arrangement is shown in 
fig. 12. It is plain that we are dealing here simply with an ordinary 
