Ser. MELANOSPEKME.E. ( 21 ) Fam. FUCACEyE. 



Plate CXXXVIII. 



FUCUS SERKATUS.— i«««. 

 t 



Gen. Chak.^ — Frond coriaceous, internally composed of densely - packed interlacing and 

 anastomosing filaments, the periphery of radiating filaments, short, simple, and 

 closely placed; air-vessels innate; receptacles terminal, or lateral and stalked, 

 containing within the periphery spherical receptacles communicating with the 

 surface by a minute pore, and containing attached to their inner surface obovate 

 spores or stalked antheridia, "or both." Name from 4)woy, "a sea-weed." 



Fucus serratiis. — Frond dichotomous, with a broad midrib, strongly 

 seiTated, the axils rather acute, the apices round, obtuse, or truncated ; 

 receptacles immersed in or near the apices of the branches, much 

 compressed. 



Fncus serraius. — Linn. Sp. PI. p. 1626 ; Fl. Lap}')- V- 365 ; Fl. Suec. p. 430 

 Huds. Fl. Angl. p. 576 ; LigUf. Fl. Scot. vol. ii. p. 902 ; Stack. Ner. 

 Brit. p. 2, t, 1 ; Turn. Syn. vol. i. p. 110; Turn. Hist. t. 90; E. 

 Bot. t. 1221 ; Lyngh. Hyd. Dan. p. 5, t. 1 ; Ag. Sp. Alg. vol. i, p. 95 

 Ag. Syst. p. 278 ; Hooh. Fl. Scot, part 2, p. 95 ; Grev. Fl. Edin. 

 p. 284; Grev. Alg. Brit. p. 15 ; Hooh Br. Fl. vol. ii. p. 267; Wyatt, 

 Alg. Danm. No. 2 ; Endl. 3rd Suppl. p. 29 ; Kiitz. Phyc. Gen. p. 352 

 JIarv. in Mack. Fl. Hih. part 3, p. 169 ; Harv. P. B. plate 47 ; Harv 

 Man. p. 19 ; Harv. Syn. p. 18 ; Atlas, plate 3, fig. 12 ; /. G. Agardh 

 Sp, Gen. Alg. vol. i. p. 211. 



Hab. — On rocky shores at half- tide level. Perennial. Winter and spring. Very 

 common. 



Geogr, Dist. — Atlantic shores of Europe ; Baltic ; Greenland. 



Description. — Root, a hard conical spreading disc. Frond one to 

 two feet or more in length, shortly cylindrical at the base, much divided 

 in a regularly dichotomous manner, with occasional lateral branches ; 

 midrib strong, gradually thinning into the flat margin, which is deeply 

 and sharply seiTated, the sen-atures slightly curved inwards, sometimes 

 assuming the form of teeth or even laciniae ; axils rather acute, apices 

 rounded or truncate. Receptacles formed of the apices of the midribs, 

 slightly swollen, at length occupying the whole apex of the frond ; con- 

 ceptacles placed immediately under the periphery, sj)ores obovate or 

 roundish ovate, at length " finally separating into eight distinct sporules " 

 {Pliyc. Brit.) ; besides the spores the conceptacles contain numei'ous 

 elongated jointed filaments or abortive spore-threads, and their inner 

 surface is formed of concentric filaments, very densely packed, but we 



