204 BRITISH SEA-WEEDS. 



It sometimes grows between tide-marks, but is generally 

 parasitical on larger algae, in deep water, whence speci- 

 mens are washed on shore. When floating, it is so trans- 

 parent as to be scarcely visible to any but a practised 

 eye. Some of my finest specimens were found whilst 

 bathing in Jersey, and I have vivid recollections of the 

 diflBculty of distinguishing them from the surrounding 

 water. 



Ceramium Deslongchampsii. Deslongchamps's 

 Ceramiwn. 



Prond two to four or five inches long, very slender 

 throughout, forkedly branched ; branches much divided, 

 either naked, or set with simple or forked branchlets, 

 which are sometimes alternate, sometimes secund, and 

 occasionally crowded, making the upper part of the frond 

 very bushy ; tips of the branches straight and spreading ; 

 nodes coated with a band of coloured cellules ; internodes 

 transparent, those of the lower part of the stem about 

 twice as long as broad, those of the branches shorter 

 than broad. Spore-clusters sessile on the sides of the 

 branches ; tetraspores set round the nodes, large, and 

 very prominent. 



The long, slender branches, and straight tips of this 

 species readily distinguish it from all other British Ce- 

 ramia. It grows parasitically on various sea- weeds, and on 

 the perpendicular sides of rocks, near low-water mark. 

 It is of a deep-purple colour, and does not adhere firmly 

 to paper unless steeped for a long time in fresh-water. 

 The fructification of this plant is very anomalous. The 

 apparent spore-clusters are not surrounded by invo- 

 lucral branchlets like those of all the other Ceramia, 

 and, what is siill more puzzling, they seem to grow on 



