130 SEAWEEDS. 



[ts botanical name is Halidrys siliquosa {Plate I., 



The Gulf- weeds (Sargassum, fig. 8) precede the Sea- 

 oak in order ; but although they are occasionally washed 

 upon our shores, they are not really natives. They are 

 well known to sailors as floating in enormous masses in 

 the North Atlantic Ocean. Columbus was in despair 

 when he encountered one of these banks of weed, and 

 seeing the ship so seriously obstructed by it, he believed 

 for a time that God had frustrated his undertaking. 

 The Gulf-weed is branched and leafy, and beset with 

 stalked air vessels which look like berries. 



Edward described a weed which he had found in 

 abundance on the coast of Cornwall. It had air-vessels 

 like berries, only they occurred in the substances of the 

 stalk, which was thus made to resemble strings of beads, 

 and little branches springing from the side of these 

 vessels, and bearing narrow flat spines, not unlike juniper 

 leaves in form. The disposition of the air-vessels proved 

 it to belong to the family of Cystoseira, the name of 

 which is taken from two Greek words, signifying bladder 

 and chain ; and the flat-pointed pinnules or fibres dis- 

 tinguish it as the species Fibrosa {Plate /., fig. 2). 

 Harvey states that this species is not found in Scotland. 

 Indeed, it is rare to meet with any Cystoseira there. 

 We were lucky, therefore, to have a specimen from Corn- 

 wall for our collection. 



There is a Heath-like Cystoseira found on the south 

 roast of England, which bears a great resemblance to the 

 plant from which it is named — a Granulated species and 

 a Fennel-like species. 



