SECT. ii. COLOSSAL ALGJE. 249 



The Laminaria digitata, commonly called the great 

 tangle, oar weed, or sea girdle, has a fibrous root, a 

 stem six or more feet long, with a wide expansion at its 

 top cut into very long narrow segments. The fronds of 

 some Laminarise are deciduous ; the stem increases in 

 size year by year, a new frond springing from the apex 

 and replacing the old one, which at last separates from 

 the point of junction with the new frond, to which it 

 is attached till the latter has attained its natural form 

 and dimensions. 



The Laminaria saccharina, called the devil's apron on 

 our northern coasts, is of a greenish olive when young, 

 brownish when old. It has a fibrous root, a stem several 

 feet long, ending in a flat ribless ribbon-like expansion, 

 always very much longer than the stem, and terminating 

 in a point. The margin of the frond is even, but wavy or 

 puckered. 



* The fruit of these three great Laminarise is imbedded 

 here and there in the surface of the frond, thickening it 

 and forming cloudy patches.' 8 It consists of thick club- 

 shaped perpendicular cells in which the endochrome is 

 ultimately divided into four parts. This is certainly the 

 case in the Laminaria bulbosa, and also in the Alaria 

 Pylaii, a species of which latter genus, the Alaria escu- 

 lenta of our own coasts, is a much esteemed British 

 dulse. 



Abundance of colossal Algse are found in the North 

 Pacific, about the Kurile and Aleutian Islands, and 

 along the deeply indented and channel- farrowed north- 

 western coast of America. The Nereocystis Lutkeana 

 forms dense forests in Norfolk Bay, and all about Sitka. 

 Its stem resembles whipcord, and is sometimes 300 feet 

 long. It is exceedingly slender at the top, where it ter- 

 minates in an enormous air-bladder six or seven feet long, 

 and about four feet and a half in diameter at its widest 



8 Berkeley's ' Cryptogamic Botany.' 



