110 College of Forestry 
swamp forest develop apparently on marshland, and marsh 
meadow seems to follow forest naturally, there remain ex- 
amples sufficiently clear to support the general rule that in 
normal sequence, grasses, sedges, annuals, ete., invade the 
marsh and transform it for a longer or shorter period into 
erassland. This is then invaded by small shrub (shrubby 
einquefoil, sweet gale, ete.), large shrub (alder, willows) 
and swamp forest (red maple, elm, black ash, ete.). In the 
case of beaver meadows and (or) vlaies, the small shrub 
stages will generally embrace a number of heath shrubs 
(sheep laurel, pale laurel, leather leaf, ete.) and while wil- 
lows and alders may appear, followed by swamp maple, black 
ash, ete., the trend is toward conifer forest. Thus tamarack, 
white cedar, balsam and black spruce invade the heath shrub. 
This condition, further emphasized in eases (as cited above) 
where mountain holly, black chokeberry, high-bush blue- 
berry, ete., invade Sphagnum-containing marsh meadow (bog 
meadows, therefore?) points to a trend of vegetation which 
finds its extreme expression in Sphagnum-heath-black spruce 
bogs. See later under Bog Vegetation, page 125. 
The case of one of the land locked bays on the shores of 
Lake Ontario, previously referred to in discussing eat-tail 
marshes, is istructive in this connection, first because it 
shows the undisturbed or natural sequence of vegetation and 
second because it bears upon the question as to whether the 
zonal segregation earlier discussed is observable in hydro- 
phytie vegetation. The basin in question was largely in 
the cat-tail marsh stage. At several points this was becom- 
ing marsh meadow. At one place the shrub stage was reached 
and this consisted of buttonbush (Cephalanthus occidentalis) 
which so far as my observation goes is common only in those 
parts of the State classified in Zones A and B, 1. e. in regions 
especially of climate moderated by lake or maritime influ- 
ence, 
