MID-LITTORAL BELT at 
local conditions of soil-moisture or shade are unusual, this grass is confined 
to levels between 1.5 and 6.5 feet. On the mud with the Spartina are found 
one other seed plant, Lilwopsis, and numerous alge, mostly small and incon- 
spicuous, except where matted together in numbers. 
If the observer now turns to the portion of the harbor’s edge bounded by 
wharves, he finds the stone walls and piles between tide-marks occupied by a 
belt of brown rockweed. Closer examination of these areas shows that they also 
are generally confined between the 1.5 and 6.5-foot levels, and that, though 
numerous other alge may be found here, the areas are dominated by the rock- 
weeds Ascophyllum and Fucus. 
These two types of vegetation, found between 1.5 and 6.5, we may designate as 
the Mid-littoral Marsh and the Mid-littoral Rockweed Association respectively. 
Together they bound practically the whole circumference of the harbor. The 
only breaks in this distinct belt or zone are the. stream-beds and two or three 
short stretches of artificial gravel beach. 
A. THE MID-LITTORAL MARSH. 
This belt, as has just been indicated, is a Spartinetum, dominated com- 
pletely in most areas by Spartina glabra. It evidently corresponds in many 
respects to the “ salt-reed swamp ” of Warming (1909, p. 223). There are two 
striking features of this marsh at Cold Spring Harbor. In the first place, there 
is no admixture of other seed plants save half a dozen small patches of Lileop- 
sis and a few scattered migrants from the next higher belt, which wanderers, 
except near fresh-water streams, never get more than a few inches below the 
6-foot level.* In the second place, this Spartina lies exactly in the middle of the 
“littoral region,” if, with Kjellman (187%, p. 57) or Oltmanns (1905, p. 167), 
we define this region as that lying between the two tide-marks. Kjellman 
chooses the extreme upper and lower tide-marks as the boundaries of this littoral 
zone, on the west coast of Nova Zembla. But at the place where he worked the 
range of tides is small and the maximum range differs but little from the mean 
range. In the harbor we are dealing with the mean tide-limits have been chosen 
as boundaries for the littoral belt because the extreme range of tides is much 
greater than the mean, and because this choice gives us a belt characterized by 
distinct vegetational types. 
At Cold Spring Harbor, where mean high water is about 8 feet above mean 
low water, and where the Spartinetum lies between 1.5 and 6.5 feet above mean 
low water, this association seems very aptly named the Mid-littoral Marsh. 
Moreover, from observations made elsewhere on Long Island and on Casco Bay, 
Maine, we are led to believe that the salt reed-grass along our whole North 
Atlantic coast will be found to be located just about midway between the mean 
tide-marks. We believe the name here used may be found generally applicable 
and clearly descriptive, for this Spartina association, wherever its vertical 
distribution is accurately determined. 
In our detailed discussion of the vegetation of the Mid-lttoral Marsh we will 
first consider the distribution of the Spartina and the other seed plants that 
are associated with it in its upper portions, and then take up the distribution 
of the algal felts or tangles and more scattered alge which form “ subordinate 
communities ” on the bottom between these seed plants. 
* Scirpus nanus also has been seen below the 6-foot level in a few places on the 
Marsh. 
