CERAMIACK^. 203 



' Phycologia/ but in his later works he has degraded it 

 to a variety. 



< C. rubrum, var. proliferum. 



Frond forked, beset on all sides with numerous simple or 

 forked branchlets ; nodes and internodes densely covered 

 with cells. Spore-clusters generally destitute of branchlets. 



This was formerly C botryocarpum, &gnveA plate 215 j 

 Harvey's ' Phycologia Britannica.' 



C. rubnuu, var. secundatom. 



Similar to the last variety, but with secund branches. 



C. rubrum, var. pedicellatum. 



Fronds sparingly branched ; branches scattered ; nodes 

 and internodes coated with coloured cellules. 

 Figured in Harvey's 'Phycologia/ plate 181. 



Ceramium diaphanum. The transparent 

 Ceramium. 



Fronds from two to six inches long, as thick as a bristle 

 below, becoming gradually thinner towards the upper part, 

 irregularly forked ; branches set with short, forked branch- 

 lets, with forcipate tips ; nodes swollen, coated with purple 

 cellules; internodes transparent, those of the main stem 

 three or four times as long as broad. Spore-clusters near 

 the tips of the branches, surrounded by involucral branch- 

 lets ; tetraspores sunk in the nodes. 



This is the largest and handsomest of our British 

 Ceramia, and is very easily recognized by its numerous 

 branches, its large size^ and distinctly chequered stem. 

 Its colour varies from a delicate pink to a dark purple. 



