Development of the Vegetation of New York State 113 
swamp where drainage has become much obstructed. Here 
the sequence — assuming it to have begun with open water 
vegetation stages—has been from Sphagnum containing 
grass and sedge marsh, to smaller heath shrub (sheep laurel, 
pale swamp laurel, leather leaf, creeping snow-berry), and 
later, to high shrub (high-bush blue berry, mountain holly, 
choke berry, etc.). The ies forest stage has been domin- 
ated by white cedar, tamarack and black spruce apparently, 
although red maple is common also, 
In the western part of this swamp where a free drainage 
channel has been maintained, one finds cat-tail marsh, marsh- 
meadow, willow and alder shrub vegetation and the normal 
broad leaved swamp species of forest trees. In this section, 
furthermore, the absence of conifers which dominate the 
more bog-like area, particularly black spruce and tamarack, 
is noteworthy. 
The question of the presence of white pine and hemlock in 
the (presumably) later stages of normal swamp forest is not 
involved with that of the other conifers mentioned here. The 
fact that very big trees of pine and hemlock do occur in typ- 
ical swamp forest seems to me noteworthy and to be deserv- 
ing of special study. Perhaps the rapid differential building 
up of the substratum as discussed later furnishes the op- 
portunity for invasion by these two conifers. 
Now, taking swamp forests of New York generally (ex- 
cept perhaps in the Adirondacks) they do not appear to 
stand in this simple developmental sequence. Repeatedly 
you will find this reversed sequence of open lake (with 
aquatic and shore vegetation), swamp-forest, swamp-shrub, 
marsh-meadow and pasture or cultivated field. The fact 
here is, that when settlement and clearing and tilling the 
land began, development of vegetation had progressed so far 
that the swamp forest stage occupied nearly all the ground 
to the lake shore, or the middle of the valley or basin, and 
