Sek. GONGYLOSrERME/E, ( 113 ) Fam. CERAMIACE.E. 



Plate CVIL 

 CEEAMIUM ACANTHONOTUM.— Cr/rm. 



Gkn. Char. — Frond filiform, single-tubed, articulated; joints, and occasionally more or 

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

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

 rounded at the base by an involucre of few short articulated spine- like ramuli ; 

 2. Tetraspores, more or less immersed in the ultimate ramuli. Name from 

 Kepa/xos, "a pitcher;" but the name is not applicable to the fruit of any species 

 of the genus as now restricted. 



Ceramium acanthonotiim. — Fronds densely tufted, much branched ; 

 branches dichotomous, fastigiate ; articulations, towards the middle, thi'ee 

 to five times longer than broad, very short upwards, without coloured 

 cells ; the dissepiments each with a stout, coloured, erect, three-jointed 

 spine, projecting upwards from its outer edge, closely approximate in the 

 apices, which are forked and strongly involute ; favellse in the axil of 

 a short incm'ved iuvolucral spine ; tetraspores very prominent, closely 

 whorled round the dissepiments of the upper branches. 



Ceramium acantkonotum. — Carm. Alg. Appin, ined. cum ic. ; /. Aff. Advers. 

 p, 26 ; Harv. P. B. plate 140 ; Harv. Man. p. 165 ; Harv. Syn. 

 p. 136 ; Atlas, plate 52, fig. 240 ; /. G. Ayardh, Sp. Gen. Alg. vol. ii. 

 p. 132. 



Ceramium ciliatum, fi acantkonotum. — Harv. in Hooh. Br. Fl. vol. ii. p. 336 ; 

 Harv. Man. 1st ed. p. 100. 



AcANTHOCERAS ShuttlewortJiianiiyin. — Kiitz. in Linn. vol. xv. p. 739 ; Kiltz. Phjc. 

 Gen. p. 381, t. 46, f. 4. 



Hab. — On rocks, shells, stones, and smaller Algse, near low-water mark. Annual. 

 Summer and autumn. Common. 



Geogr. Dist.— British Islands ? 



Description. — Root fibrous. Fronds densely tufted, often forming- 

 hemispherical tufts, very much entangled, and much divided dichoto- 

 mously, without or occasionally with lateral ramuli ; branches of nearly 

 equal diameter throughout, and veiy slender, the apices forked and 

 strongly involute ; plants one to three or even " six " inches in length, 

 the smaller specimens very much matted and interwoven, the larger 

 more loose and free. Articulations variable, towards the middle three 

 to five or even six times longer than broad, shorter upwards till lost 

 in the apices, without coloured cells ; the dissepiments opaque, and 



VOL. II. Q 



