Ser. RHODOSPERME. Fam. Ceramiee. 
Puate CXXV. 
CALLITHAMNION SPONGIOSUM, Zar. 
Grn. Cuar. Frond rosy or brownish-red, filamentous; stem either opake 
and cellular, or translucent and jointed; branches jomted, one-tubed, 
mostly pinnate (rarely dichotomous or irregular); dissepiments hyaline. 
Frut of two kinds, on distinct plants; 1, external ¢etraspores, scat- 
tered along the ultimate branchlets, or borne on little pedicels; 2, 
roundish or lobed, berry-like receptacles (/avel/@) seated on the main 
branches, and containing numerous angular spores. CALLITHAMNION 
(Lyngb.),—from xcadus, beautiful, and Oaprioy, a little shrub. 
CALLITHAMNION spongiosum; stems robust, cartilaginous, more or less 
opake and veiny, branched in every direction; branches thickly set 
with dense, quadrifarious, repeatedly dichotomous, round-topped 
branchlets; axils patent; apices short, bifid; articulations of the 
branches swollen at the jomts, twice or thrice as long as broad. 
CALLITHAMNION spongiosum, Harv. in Hook. Br. Fl. vol. ii. p. 346. Harv. 
in Mack. Fl. Hib. part 3. p. 217. Harv. Man. p.113. Wyatt, Alg. Danm. 
no. 93. Crouan, in Dezm. Pl. 
Has. On perpendicular submarine rocks, near low-water mark, and _para- 
sitically on other Algee. Annual. Summer. Dunleary (1802), WZ. 
Templeton. Larne, Dr. Drummond. Torquay, Mrs. Griffiths. Kings- 
town Harbour and Killiney, W.H.H. Salcombe, Mrs. Wyatt. Ply- 
mouth, Rev. W. §. Hore and Mr. Rohloff. Lands End and Ilfra- 
combe, Mr. Ralfs. Jersey, Miss White. Saltcoats, and Largo, Fife, 
Rev. D. Landsborough. Yalbride, Major Martin. Falmouth, Wiss 
Warren. 
Geoer. Distr. British Islands, and Atlantic shores of France. 
_ Descr. Fronds tufted, two to four inches high, with a conical outline, flaccid, 
soft, holding water like a sponge. Stems thicker than bristle, more or less 
opake and veiny, branched in every direction, and thickly clothed with 
short ramuli. Branches long, sparingly divided, but very densely clothed 
with quadrifarious secondary branches, the lowermost of which are longest, 
the rest gradually shorter upwards ; these are, in luxuriant. specimens, fur- 
nished with a second or third series, the penultimate ones being linear- 
obovate and round-topped in outline, and densely set throughout their 
length with short, dichotomous ramuli. Ramuli repeatedly dichotomous, 
with patent axils, forking at every joint ; apices short, bifid and very obtuse. 
Tetraspores elliptical, solitary, sessile in the forkings of the ramuli, triparted. 
Favelle large, and generally bi-lobed, the lobes roundish, placed at the 
summits of abbreviated branches, frequently surrounded by two or three 
dichotomous ramuli. Swéstance flaccid, membranaceous, but not gelatinous, 
destitute of gloss when dry. Colour a dull purplish- or brownish-red. Articu- 
lations of the main stems more or less filled with longitudinal veins; those 
of the branches and branchlets with a very narrow coloured tube, surrounded 
