THE SARGASSO SEA. 397 



deeply indented and channel-furrowed north-west coast of 

 America. 



Thus the Nereocystis lutkeana forms dense forests in Norfolk 

 Bay and all about Sitcha. Its stem, resembling whipcord, and 

 often above 300 feet long, terminates in a large air-vessel, six 

 or seven feet long, and crowned with a bunch of dichotomous 

 leaves, each thirty or forty feet in length. Dr. Mertens assures 

 us that the sea-otter, when fishing, loves to rest upon the colos- 

 sal air-vessels of this giant among the sea-weeds, while the long 

 tenacious stems furnish the rude fishermen of the coast with 

 excellent tackle. The growth of the nereocystis must be un- 

 commonly rapid, as it is an annual plant, and consequently 

 develops its whole gigantic proportions during the course of one 

 brief summer. 



Before proceeding to the third chief group of marine plants, 

 the red sea-weeds, or Rhodosperms, I must mention the enor- 

 mous fucus banks, or floating meadows of the Atlantic, which 

 form undoubtedly one of the greatest wonders of the ocean. 



We know that the mighty Gulf Stream, which rolls its indigo- 

 blue floods from America to the opposite coasts of the Old World, 

 flows partly southwards in the neighbourhood of Azores, and is 

 ultimately driven back again to America. In the midst of these 

 circuitous streams, from 22° to 36° N. lat., and from 35° to 65° W. 

 long., extends a sea without any other currents than those result- 

 ing from the temporary action of the winds. This comparatively 

 tranquil part of the ocean, the surface of which surpasses at least 

 twenty times that of the British Isles, is found more or less densely 

 covered with floating masses of Sargassum bacciferum. Often 

 the sea-weed surrounds the ship sailing through these savannas 

 of the sea, in such quantities as to retard its progress, and then 

 again hours may pass when not a single fucus appears. While 

 Columbus was boldly steering through the hitherto unknown 

 fields of the Sargasso Sea, the fears of his timorous associates 

 were increased by this singular phenomenon, as they believed 

 they had now reached the bounds of the navigable ocean, and 

 must inevitably strike against some hidden rock, if their com- 

 mander persevered in his audacious course. 



It is an interesting fact that the Sargasso Sea affords the most 

 remarkable example of an aggregation of plants belonging to one 

 single species. Nowhere else, according to Humboldt, neither in 



