Ser. RHODOSPERMEZ. Fam. Ceramier. 
Puate CLXXXIV. 
GRIFFITHSIA SETACEA, «%. 
Gen. Cuar. Frond rosy-red, filamentous; filaments jointed throughout, 
mostly dichotomous; ramuli single-tubed; dissepiments hyaline. 
Fructification of two kinds on distinct individuals; 1, ¢etraspores 
affixed to whorled involucral ramuli ; 2, gelatinous receptacles ( favella) 
surrounded by an involucre, and containing a mass of minute, angular 
spores. GnrirritTHsta (4g.),—in honour of Mrs. Griffiths, the most 
distinguished of British Algologists. 
GRIFFITHSIA sefacea; filaments setaceous, straight, rigid, dichotomous, or 
subdichotomous ; axils very acute; lesser branches sometimes oppo- 
site, attenuated to a point, erect; articulations cylindrical, five or six 
i longer than broad; involucres (of both kinds) pedunculate, 
ateral. 
GRIFFITHSIA setacea, 4g. Syn. p. xxviii. dg. Syst. p.144. Ag. Sp. Alg. 
voli. p.129. Grev. Fl. Edin. p.312. Hook. Br. Fl. vol. ii. p. 338. 
Harv. in Mack. Fl. Hid. part 3. p. 212. Wyatt, Alg. Danm. no. 137. 
Harv. Man. p.103. Endl. 3rd Suppl. p. 35. Kiitz. Phyc. Gen. p. 373. 
Hook. fil. Fl. Ant. vol.i. p. 191. 
ConFERVA setacea, Ellis, Phil. Trans. vol. 57. t. 18. f.e. Turn. Linn. Tr. 
vol. vii. p.107. Huds. Fl. Ang. p.599. With. vol.iv. p. 137. £. Bot. 
t.1689. Dillw. Conf. t.82. Roth, Cat. Bot. vol. iii. p. 278. 
Has. On the perpendicular sides of deep rock pools, near low-water mark, 
under the shade of larger Alge. Perennial. Fruiting in spring and 
summer. Frequent on the British shores, from Orkney to Cornwall. 
Channel Islands. 
Gzoer. Distr. Atlantic shores of Europe and America. Southern Ocean, 
especially Tasmania. 
Descr. Tufts three to eight inches long, or more, dense, frequently interwoven 
in the lower part with tangled fibres. Filaments as thick as hog’s bristle, 
sometimes not quite so thick, gradually attenuated from the base upwards, 
‘many times dichotomous at short intervals; the lesser divisions more irre- 
gular, alternate, or secund, frequently opposite; all the branches straight, 
and generally erect, with acute axils. Frequently small, root-like, irre- 
gular, horizontal ramuli issue from the sides of the main branches, and 
catching on a neighbouring branch, connect the filaments in a tangled 
web. Lesser branches gradually attenuated to the point. 4rticulations 
cylindrical ; the lower ones five or six times as long as broad, or sometimes 
more; the upper gradually shorter, all containing bags of endochrome sur- 
rounded by a narrow border. Involucres of both kinds raised on short, 
lateral peduncles, about a line in length, scattered on the sides of the 
branches, those containing tetraspores most frequently found. Tetraspores 
spherical, attached to the inner faces of the dichotomous, involucral ramuli, 
with wide borders. avelle generally binate, oval, likewise attached to 
involucral ramuli, on distinct plants. Antheridia, or minute oval bodies, 
Qa 2. 
