SEED PLANTS OF UPPER LITTORAL BELT 19 
south by 1,000 east and 200 south by 1,100 east). The lower margin of the 
S. patens belt is usually in contact with S. glabra, while at its upper margin it is 
succeeded over all this part of the Marsh by Juncus Gerardi. At one or two 
points considerable patches of S. patens are completely surrounded by the 
Juncus (150 to 300 south by 1,150 east). The large-scale map of the Marsh 
(plate x1) shows the relations of these two species there, and suggests a possible 
explanation of these islands of S. patens surrounded by Juncus, and of other 
peculiarities of its distribution (plate x1x a). It may suffice here to say that 
the islands referred to are really lower and wetter spots. It is apparently this 
greater saturation, rather than any difference in salinity, that enables the 
S. patens to crowd out the Juncus at these points. (See plate xi and fig. 3.) 
However, it must be remembered that the evaporation of the water left in these 
low spots at high tide would give rise to some concentration which would only 
be reduced by the leaching effect of heavy rains. 
The competitors of S. patens on the Marsh which may form continuous stands 
of considerable area are, in addition to the S. glabra and Juncus just mentioned, 
Distichlis, Scirpus americanus, and S. robustus. The former is found in occa- 
sional patches not many square meters in extent, on several parts of the Marsh. 
(See plates xt and xxi.) The two species of Scirpus are more abundant at the 
upper levels of this belt, around the edges of the Marsh, where the soil water is 
nearly fresh. The region of contact of 8. patens with each of these five species 
is not usually a line, but a rather broad band, in which the competing species are 
more or less intermingled. (See especially plates x1, x1x B, and fig. 3.) 
Besides these mixtures of S. patens with other dominant species along the 
tension lines, there are several other species, scattered through the stands of 
this grass on the Marsh, the distribution of which will be indicated by Professor 
Conard. The most important of these species are: Atriplex patula, Limonium 
carolimanum, Salicornia europea, Scirpus nanus, Spergularia marina, Sueda 
maritima, and Triglochin maritima. 
Spartina patens, on the west end of the Spit: On the south shore of the Spit, 
from 590 to 1,000 west, Spartina patens forms a continuous band or belt, widen- 
_ ing from 5 feet at its eastern end to 100 feet at its extreme western end (plate 
v). The general form of the area covered by it is indicated by the relative posi- 
tion of the 6-foot and 8-foot tide-lines on plate 1. The lower limit of its distri- 
bution here is at 6.5 feet or slightly lower, the upper at 7.5 to 8.5 feet. The 
plants reach a height of 4 to 6 dm. to the top of the panicle, and form a close 
turf, with often 300 to 400 leaf-bearing shoots per square decimeter. The 
rhizomes and roots penetrate to a depth of 4 or 5 inches below the surface, and 
by their interweaving give rise to a very firm sod. All other plants are wanting, 
except an occasional plant of Limonium or Sueda or felts of algee. The latter, 
of course, are confined to the surface of the soil between the Spartina stalks. 
S. patens in this region blooms freely, except near its upper and lower limits, 
beginning early in July and continuing till early September. 
At its lower limit this grass sometimes stops abruptly against the S. glabra, 
and sometimes intermingles with the latter in a strip 1 or 2 feet in width (fig. 
2). At other points along this shore Sweda or Salicornia europea may be so 
abundant near the 6.5-foot level as to dominate an intermediate strip a foot or 
two in width between the 8. glabra and the S. patens. But even in this inter- 
mediate strip numerous plants of 8S. patens and occasional ones of S. glabra are 
