130 THE COAST-FLORA OF ESSEX.
dent will allow me. I must confine myself, therefore, to a few
general remarks upon those interesting plants which occur upon
our coasts.
These plants appear to have adapted themselves to growing
in soils of different degrees of saltness, for we find that they
arrange themselves in zones. The outermost zone supports
those which grow actually in sea water, these being replaced by
other plants as we go further from the sea water. On shallow
mud flats outside our sea coast, we find beds of Grass-wrack
(Zostera marina), the weed which we have all seen washed up on
to our beaches in large quantities. The sea scarcely recedes
from these flats, which remain wet with sea water, even at low
tide.
Then, on the fringe of our coast, on the muddy flats over
which the water flows at every tide, we find the Glasswort or
Marsh-Samphire (Salicornia europaea) growing abundantly. On
ground which is a little higher than this last and is covered only
by an occasional high tide, we find a variety of plants, including
the beautiful Sea-Lavender (Statice limonium), the Scurvy-
grass (Cochlearia officinalis), the Sea-Aster (Aster tripolium), the
Golden-Samphire (Inula crithmoides), the Bristle-grass (Spartina
stricta), Sea-blite (Suaeda maritima), Triglochin maritimum, and
other plants. Then, higher up, we find the Thrift (Armeria
maritima), Wild-beet (Beta maritima), Shrubby Sea-blite (Suaeda
fruticosa), Orach (Atriplex patula), and other species of
Atriplex. These latter may be found in dry inland situations
also.
Our mud flats are usually bounded by sea-walls, erected to
protect the marshes from high tides. These sea-walls have a
flora peculiar to themselves. Narrow-leaved Cress (Lepidium
ruderale) is very common upon the Essex sea-walls, whilst
Dittander or Broad-leaved Cress (Lepidium latifolium) is abundant
in places in close proximity to them, and Hoary-cress (Lepidium
draba) frequently occurs. Another interesting plant which may
be found near our sea-walls is the Sea-Wormwood (Artemisia
maritima). This plant is also found abundantly upon the salt
steppes, where the small flower-heads are collected and sent to
Europe, being valued for their medicinal properties, an alkaloid
used in medicine and known as santonine being extracted from
them. Rushy or Sea Couch-Grass (Agropyrum or Triticum