150 BRITISH SEA-WEEDS. 



gular clusters, near the ends of the branchlets. — GELiDirM:, 

 from the Latin gelu, frost. 



The species which compose this genus are remark- 

 able for the variety of forms which they assume, and for 

 their wide geographical range. They are found on all 

 the tropical and temperate shores of the Atlantic and Pa- 

 cific Oceans. Two species have been hitherto included 

 in works on British Sea- weeds, but the claims of G. carti- 

 lagineum are so slight that I have felt compelled to omit 

 it. It is a common weed at the Cape of Good Hope, 

 whence it is frequently brought by sailors and thrown 

 overboard in British waters, and the specimens picked 

 up on our coasts have, no doubt, been derived from this 

 source. 



Gelidium corneum. The horny Gelidium. 



Frond flattened, rigid, several times pinnate ; pinnse nar- 

 rowed at the base, linear, entire, obtuse. Spores in concep- 

 tacles below the tops of the branches ; tetraspores in club- 

 shaped very obtuse pinnse. 



The varieties of this species are more numerous than 

 those of any other of our native Sea-weeds. Dr. 

 Harvey has described no less than thirteen, and it would 

 be very easy to increase the number, were it desirable 

 to do so. The differences consist chiefly in the size, 

 breadth, and branching of the frond, but there can be 

 no doubt of the specific identity of the whole series. I 

 shall therefore content myself with enumerating the 

 varieties mentioned by Dr. Harvey, and recommending 

 my readers to make as complete a collection as possible 

 of all the forms which they may find. The varieties 

 are: — 



