VEGETATION OF SHINGLE 9 



characteristic not only of seashores, but of high hills, of any 

 situation, in fact, where the supply of water is irregular. Some 

 plants frequent both situations : the Stork's Bill is found on hills 

 about eight or nine hundred feet high as well as on sandy shores ; 

 the Wild Thyme, and some of the Bedstraws are other instances. 



These plants are found not only or* the seashore, but inland, 

 in deserts where there is a certain amount of salt. Travellers 

 note in sand deserts, in addition to various species of Cacti and 

 Spurges, the Glasswort or Marsh Samphire, the Sea Plantain, and 

 various members of the Goosefoot family. 



THE VEGETATION OF SHINGLE. Sometimes the beach is covered 

 with shingle, the pebbles of which are derived partly from the 

 cliffs above, and partly from the inrolling waves, which often carry 

 with them sand and stones, depositing them on the shore. The 

 action of seaweeds, as Lord Avebury has suggested, is here of great 

 influence. " They attach themselves/ ' he says, " to the rock, and 

 grow towards the surface, many of them being floated upwards by 

 the presence of innumerable air vessels. The waves as they pass 

 drag the weeds with them, tear up the stones, and throw them on 

 the shore. Some beaches are almost entirely supplied with 

 pebbles in this way by seaweeds." On most beaches two lines of 

 seaweed may be seen, one marking the high-water at the last 

 spring tide, one the high-water line of the last tide. Between 

 these two, other lines of seaweed may occur, showing the high- 

 water level during some storm. There are three main groups 

 of seaweeds : the Olive Brown, the Red, and the Green. The 

 most common species of the first named is the Brown Bladderwrack 

 (Fucus vesiculosus) . It is like a long ribbon with a thick midrib. 

 Here and there are large bladders filled with air, which enables 

 the plant to float. The whole frond, as it is popularly called, is 

 fastened by a root-like portion to the rock. The size of this 

 seaweed varies very much : in muddy ground it may not be more 

 than an inch or two ; in more favourable situations it may be 

 3 feet long. Little indentations like pimples may be seen at 

 the summit of some of the branches ; these cavities contain the 

 reproductive organs. The Brown Seaweeds are burnt for the 

 manufacture of kelp. The Wracks are not the best ones to 



