Even the strongest seaside plants shun that part of the beach washed by the waves.  They leave that to the seaweeds.

Let us look first at some plants which have their home on the sand-hills.  Here is a fine one, like a thistle, with stiff prickly leaves, and a stiff blue stem.  In August it has blue-grey flowers.  This plant is called Sea Holly, its leaves being like those of the holly.  It has an unpleasant smell, yet its roots are used for making some kinds of sweets.

Now try to pull up a plant of Sea Holly.  You find it no easy task.  Then dig away the sand, and you see that its large roots have gone deep and far.  All these plants of sandy places grow like that.  Sand has no food or drink to give to plants.  So they send their roots out, like plants in a desert, until they find what they want.  Besides food and drink, they need a firm anchor in the loose sand.  The Sea Holly, with its roots deep down and far-spreading, can hold its own, though the gale tears at it and throws its sandy bed here and there.

We pass many small creeping plants as we walk in the dry sand.  There is a pretty Sea Convolvulus, with its stems deeply buried.  It is a cousin of the common Bindweed.  Then we see many plants of Thyme, and a few ragged bushes of Gorse.  We notice that several little plants grow near the Gorse, as if they had crept there for shelter.  The sea breeze has blown the sand into heaps, and even on these dry, thirsty hillocks we see many tufts of grass.

[Illustration:  1.  THE COMMON LOBSTER. 2.  HERMIT CRAB.]

These Couch Grasses and Dune Grasses, as they are often called, are coarse and hard.  Cattle pass them by in disgust.  Yet they are the most useful plants on the shore.  They can live and spread where other plants die.  They have very long underground stems, which go through and through the dry, loose sand.  The wind does its best to bury them in sand, but they send up hard, sharp buds, and go on living, and spreading.

Bit by bit, the sand is held together by the matted stems of these grasses.  It becomes firm, instead of loose; the wind can no longer blow it about.  Then other plants can grow in that place.  You know how men go out to the wild parts of the earth and, by hard work, make those places ready for others to settle there.  Well, the sand-grass works like that.  It prepares the way for useful plants to grow in places where they could not grow before.

Quite near to the sea we shall find a very strange little plant.  It has no leaves, only fleshy, jointed stems.  It is known as the Glass-wort, being full of a substance useful in making glass.  It belongs to a family which seems to delight in deserts and salty soil!  They have all sorts of dodges to help them live in such places.  For instance, their leaves are fleshy.  Squeeze them, and they are like wet, juicy fruit.

The Sea Beet is also a member of this family.  The Red Beet, as well as the Mangel-wurzel, we owe to this humble seaside plant.  Most of our sugar comes from the Sugar-beet.