Ser. RHoposPERME2. Fam. Gloiocladee. 
Puiate CX. 
DUDRESNAIA DIVARICATA, J. 4%. 
/ 
Gen. Car. Frond cylindrical, gelatinous, elastic; ais composed of a lax 
net-work of anastomosing filaments, coated with a stratum of closely 
combined, longitudinal fibres; the periphery of horizontal, dichoto- 
mous, moniliform filaments. Fructification, of two kinds on different 
individuals; 1, globular masses of spores (favellidia) attached to the 
filaments of the periphery. 2, external ¢efraspores, borne on the fila- 
ments of the periphery, generally terminating a ramulus. Dvupres- 
Nata (Bonnem)—in honour of W. Dudresnay. 
Dupresnat divaricata; frond filiform, pale red, very much branched ; 
branches opposite or alternate, horizontal, once or twice pinnated ; 
ramuli numerous, divaricate, irregular, obtuse. 
Dupresnata divaricata, J. 4g. Alg. Medit. p. 85. Endl. 3rd Suppl. p. 37. 
Mesoetota divaricata, 4g. Syst. Aig. p.51. Kiitz. Phyc. Gen. p. 332. 
Mesoctora Hudsoni, Harv. in Hook. Br. Fl. vol. ii. p. 386 (not of Ag.). 
Haro. in Mack. Fl. Hid. part 3. p. 186. Wyatt, Alg. Danm. no. 99. Harv. 
Man. p. 47. 
Unva rubens, Huds. Fl. Ang. p. 571. 
Has. On stones, and the smaller Algee, near low-water mark, and at a 
greater depth. Annual. Summer and autumn. Generally distr- 
buted round the British shores; more abundantly in the north. Los- 
siemouth, Mr. Brodie. Appi, Capt. Carmichael. Arran and Salt- 
Coats, Rev. D. Landsborough. Orkney, Rev. J. H. Pollexfen, Tneut. 
Thomas, and Dr. Me Bain. Sidmouth and Torbay, Mrs. Griffiths. 
Falmouth, iiss Warren. Jersey, Miss White. Aberfaw, Mr. Ralfs. 
Killiney and Kilkee, W.H.H. Howth, Miss Gower. North of 
Treland, Mr. Thompson. Roundstone Bay, Mr. Mc Calla. 
Geroer. Distr. Northern Atlantic, as far south as the French shores of the 
British Channel. Baltic Sea. 
Descr. Root minute. Fronds densely tufted, 6-8 inches long, or more, about 
half a line in diameter, preserving an equal thickness throughout, with a 
simple or forked main stem, densely clothed with lateral branches. Lowest 
branches longest, the rest gradually shorter towards the apex, so that the 
outline is pretty regularly ovate, all very patent, horizontal or divaricate, in 
some specimens pretty regularly alternate, in others generally opposite, 
flexuous, pinnate or bi-pinnate, with divaricating lesser branchlets. Ramuli 
numerous, filiform, squarrose. Substance firmly gelatinous and elastic. 
Colour a pale red, or red-brown, becoming darker in the herbarium. 
Favelle very commonly produced, imbedded in the whorled filaments of the 
periphery, to which they are attached. Tetraspores I have never seen. 
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