THE MACEOCTSTIS PTBIFEEA. 393 



e\ery year several small vessels are sent from Jersey to the 

 coast of Brittany, to fetch cargoes of sea-weeds for the farmers 

 of that island. 



The largest of indigenous sea-weeds are the Laminaria 

 saccharma and digitata, or the sugary and fingered oar-weeds. 

 Their stout woody stems, and broad tough glossy leaves of 

 dark olive-green, often twelve or fourteen feet long, must be 

 familiar to every one who has sojourned on the coast. When 

 gliding over their submerged groves in a boat, their great fronds 

 floating like streamers in the water afford the interesting 

 spectacle of a dense submarine thicket, through whose palm-like 

 tops the fishes swim in and out, emulating in activity the 

 birds of our forests. 



But our native oar-weeds, large as they seem with regard to 

 the other fuci among which they grow, are mere pygmies when 

 compared with the gigantic species which occur in the colder 

 seas. 



None of the members of this family grow in the tropical 

 waters, but they extend tq the utmost polar limits, and seem to 

 increase in size and multiplicity of form as they advance to the 

 higher latitudes. The northern hemisphere has generally dif- 

 ferent genera from the southern. To the former belong the 

 gigantic Alarias with their often forty feet long and several 

 feet broad fronds, the singularly perforated Thalassophyta, and 

 the far-spreading Nereocystis, which is only found in the 

 Northern Pacific ; while the genera Macrocystis and Lessonia 

 are denizens of the Southern Ocean. 



In the numerous channels and bays of Tierra del Fuego, the 

 enormous and singular Macrocystis pyrifera is found in such 

 incredible masses as to excite the astonishment of every traveller. 

 " On every rock," says Mr. Darwin, perhaps the best observer of 

 nature that ever visited those dreary regions, and certainly their 

 most poetical describer, " the plant grows from low-water mark 

 to a great depth, both on the outer coast and within the channels. 

 I believe, during the voyages of the Adventure and Beagle, not 

 one rock near the surface was discovered which was not buoyed by 

 this floating weed. The good service it thus affords to vessels 

 navigating near this stormy land is evident, and it certainly 

 has saved many a one from being wrecked. I know few 

 things more surprising than to see this plant growing and 



