2 50 MACROCYSTIS. PART n. 



part, the lower extremity passing into the stem. This 

 huge air-vessel, which is the usual seat of the sea otter, 

 is crowned with a tuffc of twin leaves mostly rising on 

 five stalks. These leaves, which are membranous and 

 lanceolate when young, and from one to two feet long 

 and two inches broad at the centre, are only marked 

 with a few faint nerves, but they ultimately split length- 

 wise, cover a large space, and attain a length of twenty- 

 seven or thirty feet, or even more. The growth of the 

 Nereocystis must be enormously rapid, since it is an 

 annual, and must therefore develop its whole gigantic 

 proportions in one summer. 9 Boats cannot pass through 

 the floating masses of this plant, whose stem is used for 

 fishing lines, and whose cylindrical air-vessel serves as 

 a siphon for pumping water out of boats. 



The Thalassiophyllum Clathrus is also an inhabitant 

 of the Russian coast of North America. It is about 

 six feet high, very bushy and branched, each branch 

 bearing a broad leaf at its extremity which unfolds 

 spirally, and by this gradual development produces the 

 stem with its branches and lateral divisions. A spiral 

 border wound round the stem indicates the growth of 

 the frond, which presents a large convex bent lamina 

 without nerves, or a leaf of which one-half is wanting. 

 Numerous long narrow perforations, arranged in a ra- 

 diating form, give it the appearance of a cut fan. 



The Macrocystis pyrifera and the Laminaria radiata 

 are the most remarkable of marine plants, for their 

 gigantic size and the extent of their range. They 

 are met with on the antarctic coasts two degrees 

 nearer the pole than any other vegetable, except the 

 Diatomacese. The stem of the Macrocystis is slender, 

 smooth, round, and slimy, rising from a fibrous root, 

 like other Laminarise, and bearing at its tip a lanceolate 



9 Berke^y's ' Cryptogamic Botany.' 



