THE SARGASSO SEA. 307 
jeeply indented aud 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 
zircuitous 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 
