Ser. MelanospermejE. Fam. Dictyotece. 



Plate CCCXXVI. 



DICTYOSIPHON F(ENICULACEUS, Grev. 



Gen. Char. Root a small, naked disc. Frond filiform, tubular, branched j 

 its walls composed of several rows of cells, of which the inner are 

 elongated, and connected in longitudinal filaments ; the outer small, 

 polygonal, forming a membrane. Fructification, solitary or aggre- 

 gated naked spores, scattered irregularly over the surface. Dictyo- 

 siphon (Grev.), — from Blktvov, a net, and a-Kpau, a tube; because the 

 frond is hollow, and has a netted surface. 



Dictyosiphon famiculaceus ; frond setaceous, very much branched; 

 branches capillary, decompound; ramuli subulate, alternate or scat- 

 tered, rarely opposite. 



Dictyosiphon foeniculaceus, Grev. Alg. Brit. p. 56. tab. viii. Iloofc. Br. Fl. 

 vol. ii. p. 279. Wyatt, Alg. Danm. no. 205. Harv. in Mack. Fl. Hib. 

 part 3. p. 176. Harv. Man. ed. 1. p. 32. ed. 2. p. 40. /. Ag. Sp. Alg. 

 vol. i. p. 82. Kiltz. Sp. Alg. p. 485. Aresch. Phyc. Scand. p. 147. t. 6, 

 7,8 (in part). E. Bot. Suppl. t. 2746. 



Scytosiphon foeniculaceus, Ag. Sp. Alg. vol. i. p. 164. Ag. Syst. p. 258. 

 Lyngb. Hyd. Ban. p. 63. t. 14. 



Fucus subtilis, Turn. Hist. t. 234. 



Conferva foeniculacea, Huds. Fl. Angl. vol. ii. p. 594. Light. Fl. Scot. vol. ii. 

 p. 981. 



Conferva marina foeniculacea, Bill. Hist. Muse. p. 16. t. 2. f. 8. 



Hab. In rock-pools, between tide-marks, either on stones, or growing pa- 

 rasitically on other Algae. Annual. Spring and summer. Common 

 on the coast. 



Geogr. Distr. Atlantic shores of Europe and of Korth America. Baltic Sea. 



Descr. Root a very small disc. Stem from six inches to one or two feet 

 or more in length, varying from a quarter to half a line in diameter, gene- 

 rally undivided, but densely furnished throughout its entire length with 

 lateral branches. Branches long, similar to the stem, and excessively 

 branched in a very irregular manner. Sometimes the secondary brandies 

 arc very densely set, capillary, elongated and simple, or nearly so. Some- 

 times they are short, curved, and twice or thrice divided. Commonly they 

 are decompound and bushy, plentifully furnished with subulate, acute ramuli, 

 which are either scattered or rarely opposite. When young, the whole 

 frond is densely clothed with pellucid, jointed hairs. It is at first solid, 

 but the central cells, which are much larger than the rest, are also weaker 

 and soon perish, leaving the stem and branches fUtular. The walls of the 

 tube are composed of several layers of longitudinally connected cylindrical 

 cells, of which the inner ones are elongate, the real gradually shorter; the 



z 2 



