Development of the Vegetation of New York State 101 
forming aptitudes of some of its growth forms and their tol- 
erance of partial submergence (lake rush sometimes stands 
in a five-foot depth of water) rapidly encroaches on the 
shallow water associations. One may often find water lilies, 
Potamogetons and the like persisting in small open-water 
patches in a marsh. 
Marsh Vegetation. 
A new vegetation type appears when the substratum lies 
at approximately mean water level so that with seasonal 
fluctuations it may lie exposed at low water and submerged at 
high water stages. This is the case especially when the 
substratum has been built up under water either by vegeta- 
tion chiefly or by stream sediment and vegetation. W There 
the normal land contour lies so that the soil is habitually 
water soaked and periodically submerged, swamp forest has 
developed in our area, but even here there is reason to think 
that marsh and marsh-meadow stages preceded it (See below 
under swamp forest). 
In this marsh type the new condition of environment lies 
essentially in the absence of the protective and buoyant effect 
of water to sustain weak, soft-tissued spindling shoots or 
leafstalks of floating leaves. The plant is anchored in the 
substratum by freely branching roots and generally by an 
extensive dey elopment of rhizomes (root stock s) but the 
vertically growing parts (long leaves of cat-tail and the tall 
leaf and flower bearing stem of this; the wand-like stems of 
lake rush, the expansive leaves of royal and cinnamon fern) 
rise clear of any water protection or support. This means 
that such a plant must meet the stress of weather, winds, rain 
storms, ete., or in high water stages, of violent current 
or wave action (notably in Montezuma Marshes) and there- 
fore a corresponding degree of firmness is required in stem 
and leaf which is pretty generally supplemented by a type of 
erowth form such as those of cat-tail, lake rush, and sedges 
and grasses generally, capable of distributing the stress 
among a multitude of flexible leaves or wand-like stems. A 
certain firmness of substratum is required in this case. If 
