210 BRITISH SEA-WEEDS. 



Ceramium flabelligerum. The fan-bearing 

 Ceramium. 



Fronds growing in tufts, two to four inches high, taper- 

 ing upwards, irregularly forked ; branches fan-shaped, acute 

 at the tip, forcipate, very slightly incurved, the outer edge of 

 each node armed with a single, short, awl-shaped, three-jointed 

 spine ; the internodes of the lower part of the frond about 

 twice the length of their diameter, those of the upper part 

 about as long as broad ; both nodes and internodes covered 

 throughout with small, coloured cells. Spore-clusters at- 

 tached to the upper branches, two or three together, sup- 

 ported by long, taper, involucral branchlets ; tetraspores 

 large, whorled round the internodes. 



The cell-coated internodes, combined with the armed 

 nodes, distinctly separate this species from all other Ce- 

 ramia. C. rubrum possesses the former character ; but 

 no species has both. This is a rare plant, but I have 

 collected it more than once in Jersey. It grows on 

 sea-weeds, between high- and low-water mark, in sum- 

 mer and autumn. 



Genus XCVI. PTILOTA. 



Frond cartilaginous, compressed, much divided in a comb- 

 like, pinnate manner, opake, composed of a single-tubed, 

 jointed axis, surrounded by two layers of cells; those near- 

 est the axis large, roundish, those on the surface minute, 

 coloured. Spore-clusters nestling among involucral branch- 

 lets, at the tips of small branches ; spores angular, nu- 

 merous, enveloped by a transparent membrane ; tetraspores 

 tripartite, formed, either singly or several together, at the 

 tips of the ultimate branchlets. — Ptilota, from the Greek 

 ptilotos, feathered. 



The two species of this genus which are included in 

 our flora are somewhat similar in external appearance 



