168 THE ESSEX NATURALIST
sp., Suaeda and Spergularia all occur here, and just by the
angle of the sea-wall there is a large patch of Aster
Tripolium. Here, and in most places in which it occurs
on the drained marsh, this plant has numerous purple ray
florets. West of Site 4B, Greek 4 lies between arable land
and the sea-wall, and the banks are steeper. Here there is
no soft mud near the water-level, so that the banks are
colonised mainly by Agropyron pungens and other grass-
land and sea-wall species. Scattered plants of Aster
Tripolium are also found. When the creek dries up in the
early summer, Atriplex hastata L., Juncus Gerardi and
Suaeda maritima colonise the lower parts of the banks, and
Scirpus maritimus L.. with Triglochin maritimum and
Suaeda maritima, fills the base of the creek. The transect
at Site 4C illustrates the positions of the various species, but
does not show as high a proportion of Scirpus as is found in
the creek between 4B and 4C. Further west, trampling of
the banks by grazing cattle again allows for colonisation
by the species of wet, saline mud found east of 4B.
The other specially-dug ditches are all far less saline than
Creek 4. In Creek 2 the water contains 1.33 grams chloride
per litre (T3 per cent). Water remains in this creek even
in summer, although the depth is decreased. Ranunculus
Baudotii Godr. and Zannichellia palustris L. are found in
the water here, and Scirpus maritimus roots in the creek
base and grows in the standing water. On the banks, which
are fairly trodden down by the cattle, are plants of the species
of the pasture-land and also plants of Carex otrubae Podp.,
Rumex conglomeratus Murr. and Alopecurus geniculatus L.
In the water of the other ditches surrounding this part of
the pasture-land, Ranunculus Baudotii is again found, and
the margins of the beds are lined with Scirpus maritimus.
Juncus Gerardi also occurs in scattered clumps on the banks
of Creeks 16 and 17.
Creek 5 has a salinity of 2.35 grams per litre (.23 per-
cent), and is filled along its entire length by Scirpus mari-
timus. The zone between the creek and the ploughed land
is covered with Agropyron pungens.
Creeks 18-21 and the southern half of Creek 6 show the
same two species in exactly similar positions. Where