ALG^. 85 



This weed girds the globe in the southern tempe- 

 rate zone, but not in the tropics or northern hemi- 

 sphere ; its southern boundary being very much 

 determined by the position of the ice, and its northern 

 boundary by the currents and temperature of the 

 water. 



The above is not the only gigantic sea-weed which 

 is found in the Antarctic Ocean, since there is another 

 which vies with it in magnificence. This is Lessonia, 

 or, we should rather say, the species of Lessonia, for 

 there are two or three, which differ only in specific 

 details, " These are dichotomously branched trees, 

 with the branches pendulous, and again divided into 

 sprays, from which hang linear leaves from one to 

 three feet in length. The trunks usually arc about 

 from five to ten feet long, as thick as the human 

 thigh, rather contracted at the very base, and again 

 diminishing upwards. The individual plants arc 

 attached in groups, or solitary, but gregarious, like 

 the pine or oak, extending over a considerable 

 surface, so as to form a miniature forest, which is 

 entirely submerged during high water, or even half 

 tide, but whose topmost- branches project above the 

 surface at the ebb. To sail in a boat over these 

 groves on a calm day affords the naturalist a delight- 

 ful recreation, for he may there witness, in the 

 Antarctic regions, and below the surface of the ocean, 

 as busy a scene as is presented by the coral reefs of 

 the tropics. The leaves of the Lessonia are crowded 

 with Sertnlarice and Molluscs, or encrusted with 

 Flustrce ; on the trunks parasitic algae abound, 

 together with chitons, limpets, and other shells ; at 



