Ser. Melakospeime.*. Pam. Sporochnoidea. 



Plate CCCXII. 



DESMARESTIA VIRIDIS, Lamour. 



Gen. Char. Frond linear, either filiform, compressed, or flat, distichously 

 branched, cellular, traversed by an internal, single-tubed, articulated 

 filament ; producing, when young, marginal tufts of byssoid, branching 

 fibres. Desmarestia {Lamour.), — in honour of A. G. Desmarest, a 

 celebrated French naturalist. 



Desmarestia viridis -, frond cylindrical, filiform, repeatedly pinnate; 

 pinnae and pinnulse capillary, exactly opposite, patent. 



Desmarestia viridis, Lamour. Ess. p. 25. Endl. 3rd Suppl. p. 28. Harv. 

 Man. ed. 2. p. 24. Kiitz. Phyc. Gen. p. 344. Kiltz..Sp. Ag. p. 570. 



Dichlokia viridis, Grev. Alg. Brit. p. 39. t. 6. Hook. Br. Fl. vol. ii. p. 274. 

 Harv. in Mack. Fl. Hib. part 3. p. 173. Wyatt, Alg. Damn. No. 56. /. Ag. 

 Sp. Alg. vol. i. p. 164. 



Sporochnus viridis, Ag. Sp. Alg. vol. i. p. 154. Ag. Syst. p. 259. Grev. Fl. 



Edin.y.%%1. 

 Chordaria viridis, Ag. Syn. p. 14. Hook. Fl. Scot, part 2. p. 98. 

 Gigartina viridis, Lyngb. Hyd. Ban. p. 44. 



Fucus viridis, Fl. Ban. t. 8S6. Esper, Ic. Fuc. t, 114. Stack. Ner. Brit. 

 1. 17. Turn. Syn. vol. ii. p. 397. Turn. Hist. t. 97. E. Bot. t. 1669. 



Hab. In the sea, growing on stones and the larger algae between tide- 

 marks, and below low-water mark. Annual. Spring and early 

 summer. Not uncommon. 



Geogr. Distr Atlantic shores of Europe and America. Northern Pacific, and 

 Southern and Antarctic Oceans. 



Descr. Root a scutate disc. Fronds from two to three feet in length, filiform, 

 from a quarter to half a line in diameter at the base, gradually attenuated 

 upwards to an extreme fineness, excessively branched, having an ovale 

 outline, the lower branches long, the upper gradually shorter. All the 

 branches, and every one of the lesser divisions, down to the most minute 

 ramulus, are exactly opposite and distichous; the larger divisions patent or 

 nearly horizontal, the lesser gradually more erect. In a young state the 

 branches and ramuli terminate in excessively tine, articulated, confervoid 

 filaments, which gradually become coated with cells, and thus opake ; the 

 confervoid filament being- then encased, and changed into the axis of the com- 

 pound frond. Structure densely cellular, with large air-cells dispersed through 

 the cellular substance ; the axile filament very slender. Colour, when grow ing, 

 a deep bro\vn-oli\ e, or "foxy," quickly becoming \ erdegri>-green when re- 

 moved from the water. Substance soft and flaccid, soon decomposing. 



