Ser. RHODOSPERME. Fam. Ceramiee. 
Puate V. 
CALLITHAMNION GRACILLIMUM, 4. 
Gen. Cuar. Frond rosy, or brownish red, filamentous; stem either opake 
and cellular or translucent and joimted ; branches jointed, one-tubed, 
mostly pmnate (rarely dichotomous or irregular) ; dissepiments hyaline. 
Fruit: 1, external tetraspores, with colourless borders, scattered along 
the ultimate branchlets or borne on little pedicels; 2, roundish or 
lobed berry-like receptacles (favel/@), seated on the main branches, 
and containing numerous seeds. 
CaLLiTHaMNion gracillimum; frond distichously branched, fan-shaped ; 
stems capillary, decomposito-pimnate ; upper plumules long, narrow, 
ovate or lanceolate, spreading, bi-tri-pmnate ; joints of the stem cylin- 
drical, three or four times, of the pimnee two or three times longer than 
broad, veinless ; tetraspores borne on the tips of the pinnules. 
CaLLITHAMNION gracilliimum, 4g. Sp. Alg. vol. ii. p. 168. Harv. in Hook. 
Br. Fl. vol. ii. p. 345. Wyatt. Alg. Danm. no. 45. Endl. 3rd Suppl. p. 34. 
Kiitz. Phyc. Gen. p. 372. 
Has. Very rare. On mud-covered perpendicular rocks, near low-water 
mark. Annual. Summer. On the pier at Torquay, Mrs. Griffiths. 
Milford Haven, Mr. Ra/fs. Falmouth, Miss Warren. 
Geoer. Distr. Atlantic coast of France, Grateloup. South and west of England. 
Desc. Fronds tufted, 1-4 inches high, exceedingly slender, distichous, irregu- 
larly branched; main branches rather few, simple, 1-2 inches long, un- 
equally but closely plumulate along their whole length, having an ovate or 
lanceolate figure, and all attenuated at the pomt. Lower plumules short, 
vaguely pinnate; upper elongate, lanceolate, spreading, bi-tri-pinnate. All 
the divisions alternate, and a branchlet usually springing from every joint. 
The colour, when quite recent, is a deep red, becoming rose-red in fresh 
water, and if kept long in that medium the frond discharges a quantity of 
brilliant carmine powder, which permanently stains paper. Tetraspores very 
minute, elliptical, borne on the tips of shortened pinnule. Favel/e roundish 
or irregularly lobed, springing from the larger branches. Substance deli- 
cately membranaceous and flaccid, closely adhering to paper. 
This extremely elegant plant, perhaps truly the most graceful 
of the very beautiful genus to which it belongs, was first gathered 
on the shores of France by M. Grateloup, who communicated 
specimens to the elder Agardh, by whom it was published in the 
year 1828. Shortly afterwards the indefatigable Mrs. Griffiths 
c 
