- 
Ser. RHODOSPERMEA. Fam. Ceramiee. 
Puate CXL. 
CERAMIUM ACANTHONOTUM, Carn. 
Guy. Cuar. Frond filiform, one-tubed, articulated ; the dissepiments coated 
with a stratum of coloured cellules, which sometimes extend over the 
surface of the articulation. Fructification of two kinds, on distinct in- 
dividuals; 1, ¢e¢traspores, either immersed in the ramuli, or more or 
less external; 2, sessile, roundish receptacles (favellz), having a pel- 
lucid hmbus, containing minute, angular spores, and subtended by one 
or more short, involucral ramuli. Crramium (Roth),—from kepapos, 
a pitcher, but the fruit is not pitcher-shaped. 
Crramium acanthonotum ; frond slender, of nearly equal diameter through- 
out, rigid, repeatedly dichotomous, fastigiate, the apices strongly 
involute; articulations pellucid, those of the middle of the stem 
several times longer than broad, the upper gradually shorter; dissepi- 
ments coloured, armed on the outer edge with a single robust, broadly 
subulate, coloured, three-jointed prickle ; tetraspores erumpent, whorled 
round the joint; favellze roundish, subtended by a solitary, incurved 
ramulus. 
CERAMIUM acanthonotum, Carm. Alg. Appin. ined. cum ic. J. Ag. Advers. 
p. 26. 
CERAMIUM ciliatum, 8. acanthonotum, Harv. in Hook. Br. Fl. vol. ii. p. 336. 
Harv. Man, p.100. 
AcanTHoceras Shuttleworthianum, Kitz. in Tinn. t. 15. p. 739. Kiite. Phyc. 
Gen. p. 381. t. 46. f. 4. 
Has. On exposed rocks, near low-water mark, and on the smaller Alge. 
Annual. Summer and autumn. Not uncommon. Appin, Capt. 
Carmichael. Aberdeen, Dr. Dickie. Torbay, Mrs. Griffiths, Plymouth, 
Messrs. Hore and Rohloff. Common in the west of Ireland, W.H.H. 
Youghal, Miss Balt. 
Gerocr. Distr. The British Islands. 
Descr. Fronds very densely tufted, when old forming intricate and often matted 
bunches, from two to six inches in diameter, slender, about as thick as 
human hair, of equal diameter throughout, excessively divided dichotomously 
and more or less furnished with lateral dichotomous branchlets; in old 
specimens these latter become in their turn repeatedly divided, and, issuing 
along the whole of the lower parts of the frond, serve to render the tufts so 
compact and closely matted, as they eventually become. 4vils patent in 
all parts of the frond; apices strongly rolled inwards. Articulations 
colourless, cylindrical, those of the lower parts of the stem several times 
longer than broad; the upper gradually shorter, and the ultimate ones 
extremely short, many times shorter than broad. Dvéssepiments coated with 
a broad, deeply coloured, well-defined band of minute, angular cellules ; 
each with a solitary, robust, coloured, three-jointed, broadly subulate, or 
deltoid, very acute prickle on its outer margin. Tetraspores very large, 
with broad pellucid pericarps, erumpent from the joimt, whorled. Favelle 
globose, lateral, subtended by a single, strongly incurved ramulus. Colour 
of the tufts dark purple. Substance rigid, imperfctly adhering to paper. 
FQ 
