BEACH PLANTS, 'Idled STRAND, SHORE, or LITTORAL PLANTS. Plants that grow above the waterline along the shores of oceans or great lakes. They form one of the edaphic groups of xerophytes (q.v.). The beach, as the term is here used, is composed of sand or gravel. and is essentially a product of wave-action; it comprises the zone which is, or has been, worked over by the waves. It is commonly de limited on the one side by the water-line, and on the other by dunes or sea-cliffs. The lower por tion of the beach is washed by the waves of sum mer storms, and is devoid of life. Water-plants cannot grow there because of excessive exposure, while land-plants are excluded because of fre quent wave-action. Beyond this zone is another, which is washed by the high waves of winter storms; here annual plants are found, but not permanent perennials, since the winter waves de stroy them. Beyond the reach of any but excep tional waves is the upper beach, and here the conditions for life are much improved; not only annuals, but also biennials and perennials, be come more or less abundant.
The most characteristic type of beach plant is the succulent annual, of which the Sea Rocket (Cakile) may be considered a good example, since it is a common beach plant along the ocean shores of America and Europe, and also along the shores of the Great Lakes. The development of succulent annuals on the beach is a fact of great interest, since this type of vegetation is pe culiarly characteristic of deserts. This suggests
that the beach is a highly xerophytic habitat ; and such is indeed the case, for there is no habitat in ordinary climates where the exposure to wind, light, heat, and cold, is greater than here. High er up on the beach there are often found biennial rosette plants, and perennials with long, under ground stems, as in the Beach Pea ( Lathyrits marit im us) and in the Sand Reed (A mmophila ) The vegetation of beaches is almost always sparse. But few species can endure the severe conditions, and even in the case of these few spe cies, the individuals are commonly scattered. As a consequence, the sandy or gravelly roil gives the dominant tone to the landscape, as is the case in deserts. A comparison of the ocean beach with the beach of the Great Lakes brings out the fact that the floras are almost identical. It might he supposed that the influence of salt (see HALOPHYTES) would be indicated by a different assemblage of plants along the seashore, but scarcely any inland and coastal plant societies are so much alike as those of lake and ocean beaches. This fact shows that the xerophytic character of the beach conditions determines the nature of its flora. See ECOLOGY.