Ser. MELANOSPEEME.^. ( 31 ) Fam. SPOROCHNOIDEiE. 



Plate CXLII. 

 DESMAEESTIA LIGULATA.— i«mo«r. 



Gen, Char. — Frond cartilaginous, cellular, composed of three strata of cells, surrounding 

 a single-tubed jointed axis ; cells of tlie inner stratum very minute, of the second 

 rather large, those of the periphery -very small ; "producing, when young, mar- 

 ginal tufts of byssoid, branching fibres." Name in honour of A. Gt. Desmarest, 

 a celebrated French Naturalist. 



Desmarestia ligulata. — Frond compressed or flat, with a very obscure 

 midrib, repeatedly pinnate ; pinn£e and pinnulse opposite, linear-lanceolate 

 or elliptical, acute at each end. 



Desmarestia ligulata. — Lamour. Ess. p. 25; Grev. Alg. Brit. p. 37, t. 5 ; Hook. 

 Br. Fl. vol. ii. p. 273; Wyatt, Alg. Damn. No. 55 ; Endl. 3rd Suppl. 

 p. 28 ; Kiitz. Phyc. Gen. p. 343 ; Harv. in Mack. Fl. Hih. part 3, 

 p. 172 ; Harv. P. B. plate 115 ; Harv. Man. p. 23 ; Harv. Syn. 

 p. 21 ; Atlas, plate 5, fig. 17 ; Harv. N. B. A. part 1, p. 78; /. G. 

 Agardk, Sp. Gen. Alg, vol. i. p. 169. 



Desmia ligulata. — Lyngh. Hyd. Han. p. 33, t. 7. 



Sporochntis ligulatus. — Ag. Sp. Alg. vol. i. p. 158; Ag. Syst. p. 261; Grev. Fl. . 

 Edin. p. 287 ; Spreng. Syst. Veg. vol. iv. p. 330. 



Laminaria ligulata. — Hook. Fl. Scot, part 2, p. 99. 



Fucus ligulatus. — Lightf. Fl. Scot. p. 946, t. 29 ; Turn. Syn. p. 99 ; Turn. Hist. 

 Fuc. t. 98 ; Sm. E. Bot. t. 1636. 



Fucus herhaceus.—Huds. Fl. Angl. p. 582. 



Hab. — On rocks and stones in submarine pools, near low- water, and to a greater depth. 

 Annual. Summer. Common. 



Geogr. Dist. — European Atlantic ; Cape Horn (Dr. Hooker). 



Description. — Root, a broad conical disc. Frond from one to two feet 

 in length or more, very variable in breadth, almost linear, linear-lanceolate, 

 or broadly lanceolate or elliptical, and from half a line to an inch and a-half 

 or even more, with a very short more or less cylindrical base, gradually 

 becoming flattened or compressed ; in the latter case with a very obscure 

 midrib and two-edged, in the former with a midrib narrow but more 

 distinct and pinnated, repeatedly pinnate almost from the base ; pinnae 

 and pinnidse distichous, very irregular in length, the smaller simple, 

 the larger again pinnate, bipinnate, or even in very luxuriant specimens 

 tripinnate ; all the divisions similar in form to the main stem, being 

 linear, linear-lanceolate, or even broadly lanceolate or elliptical, acu- 

 minate at the summit, and attenuated into a very narrow footstalk at 



