MARINE PLANTS. 55 



anchors. Frequently a simple conical disc suffices to bind the 

 weatherbeaten alga to its native cliff; and as the hardy plant 

 advances in growth, and as new props are required to support 

 the additional weight, the branches of the root lengthen, and 

 others are gradually added, till a compact mass of interwoven 

 fibres is formed, each of which takes a separate gripe of the rock 

 by the disc at its extremity, so that their united powers of re- 

 sistance are able to bid defiance to the swelling flood. 



The Laminariae, or Oar-weeds of our coasts, with their long 

 broad leaves cloven into a great number of ribbon-like segments, 

 sufficiently prove the strength of an adherence which enables 

 such vegetable masses to bid defiance to the rocking waves ; but 

 what are these to the submarine forests in the channels of Tierra 

 del Fuego, where the Macrocystis pyrifera rises from depths of 

 from one hundred and fifty to two hundred feet, and then con- 

 tinues to float many fathoms on the surface of the sea ! 



f I know few things,' says Mr. Darwin, 'more surprising than 

 to see this plant growing and flourishing amidst those great 

 breakers of the western ocean, which no mass of rock, let it be 

 ever so hard, can long resist. The stem is round, slimy, and 

 smooth, and seldom has a diameter of so much as an inch. A 

 few taken together are sufficiently strong to support the weight 

 of the large loose stones to which in the inland channels they 

 grow attached, and some of these stones are so heavy that, when 

 drawn to the surface, they can scarcely be lifted into a boat by 

 one person.' Fancy how beautifully calculated the strength of 

 the resistance must be to withstand the vast strain of such a sea ! 

 No doubt many a Macrocystis is torn from the spot on which it 

 grew and cast into the open ocean ; but in spite of storm and 

 breakers, the species maintains itself from century to century, 

 for the strength with which it clings to the naked rock, and faces 

 the fury of the elements, has been poised by the wisdom of a God. 



Very different from the roots of the rock-bound Alga? are 

 those of the Zostera marina, or Grass-wrack, a flowering sea- 

 plant, which forms extensive submarine meadows on sandy 

 shores. On this loose soil a simple superficial attachment would 

 have been of no avail, but the long creeping stems of the Grass- 

 wrack send forth long roots at every joint, which, plunging 

 deep into the sand, are most admirably adapted for securing a 

 firm establishment on this unstable foundation. 



