Ser. GONGYLOSPERME/E. (101 ) Fam. CERAMIAOEyE. 



CERA]\riUM GRACILLIMUM.— G^r/)f. d Barv. 



Gen. Citar. — Frond filiform, single-tiilied, articulated; joints, and occasionally more or 

 less of the articulatiou, pervaded by coloured cells. Fructification of two kinds, 

 on distinct plants : 1. Favellse, roundish, with a pellucid limbus, and generally sur- 

 rounded at the l)ase by an involucre of few short articulated spine-like ramuli ; 

 2. Teti'aspores, more or less immersed in the ultimate ramuli. Name from 

 Kfpafj.os, "a pitcher ; " but the name is not applicable to the fruit of any species 

 of the genus as now restricted, 



Ceramium gracillimum. — Fronds cylindrical, very slender ; main 

 branches dichotomous, scarcely tapering upwards, everywhere beset 

 with short dichotomously nuiltifid ramuli ; articidations of the main 

 divisions five to six times as long as broad, of the ramuli many times 

 shorter than broad ; favellae terminal on the ramuli, involucrate. 



Ceramium gracillimum. — Harv. P. B. plate 206 ; Harv. Man. p. 163 ; Ilarv. 

 Syn. p. 133; Atlas, Y,h.tQ 51, fig. 232; /. G. Arjardh, Sp. Gen. Alg. 

 vol, ii. p. 118. 



Ceramium flaccidum. — Harv. in Herh. 



HoRMocERAS gracilUmum. — Kiitz. in Linn. vol. xv, p. 733 ; Kiitz. Phyc. Gen. 

 p. 378. 



Hab. — On shells and the smaller Algre at extreme low water. Annual. September. 

 Kilkee, Coast of Clare {Dr. Harvey, 1844) ; Mewstone, Plymouth {Eev. W. S. Hore and 

 Dr. Cocks) ; Penzance {3fr. Ralfs). 



Geogr. Dist. — Mediterranean Sea ; Atlantic coasts of France. 



Description. — Fronds tufted, two to three inches long, and very 

 slender, branched; main branches subdichotomous, of almost equal 

 diameter throughout, rather distant and suberect, suddenly tapering at 

 the summit, everywhere beset at the distance of one to three joints, with 

 short many times dichotomous ramuli ; apices forked and incurved. 

 Articulations, near the middle, five or six times longer than broad, rather 

 shorter upwards, those of the apices and ramuli very short, about twice 

 as broad as long ; dissepiments slightly swollen. Substance rather soft 

 and flaccid, more or less adhering to paper. Colour, " a dark reddish 

 purple." — Phyc. Brit. Favellee terminal, on slender lateral branches, 

 with three to four involucral spines, which are long, spreading, and 

 frequently forked. 



We have never met with this species on the east coast, and only know 

 it from dried specimens, and these somewhat imperfect. 



