VEGETATION OF THE SEA-COAST 389 



selves by means of long roots, and produce stems, at first 

 erect, but which are soon laid prostrate by shingle rolled 

 over them by the waves. From the horizontal branches, 

 new erect shoots arise and grow above the surface ; these 

 in turn are bent over and covered, and so the process is 

 repeated. The plant, thus growing along the line of the 

 moving shingle, travels obliquely to the crest of the bank, 

 where it establishes itself. From the prostrate stems, 

 a tangle of adventitious roots arises, which, together with 

 the mat of shoots, serves to prevent the removal of shingle 

 as the water runs down the bank. Further, the shoots 

 arrest the landward flew of shingle, and the crest becomes 

 raised beyond the reach of the highest tides ; thus a sea- 

 wall is formed which effectually checks the force of the 

 waves. The Sea Blite, therefore, may, by its vegetative 

 growth and power of rejuvenescence, become a valuable 

 protector of the land against the incursions of the sea. 



Some of the plants on the shingle beach are halophytes, 

 e. g. the Oraches and Beet, Sea Blite, and Sea Campion, 

 which are able to grow in parts influenced by the salt water. 

 Others are characteristic of sand-dunes, especially if the 

 beach has been formed on a bed of sand, e. g. Sea Purslane, 

 Horned Poppy (Glaucium luteum), Biting Stonecrop {Sedum 

 acre), Viper's Bugloss (Echium vulgar e), and Sea Pea (Lathy - 

 rus maritimus) ; or strand-plants, e. g. the Saltwort (Salsola 

 Kali). Frequently plants from the neighbouring fields and 

 cultivated ground occur, their seeds having been carried 

 to the beach by the wind or by birds, e.g. Elder (Sam- 

 bucus nigra), Woody Nightshade (Solatium Dulcamara var. 

 marinum), Curled Dock (Rumex crispus), Creeping Butter- 

 cup (Ranunculus repens), Herb Robert (Geranium Rober- 

 tianium var. purpureum) . On the more sheltered and stable 

 landward slope of the beach, plants are more abundant, and 

 their remains form a humus on which eventually a grassy 

 carpet may form. In this way the open association of the 



