FUCUS. 19 



Rocky shores, most abundant. (3. in salt-marshes, occasionally flooded 

 by the sea. Very variable in size and general appearance, often destitute 

 of air-vessels. j3. is a remarkable state, 1 or 2 inches high, scarcely a line 

 wide, and of a tawny yellow colour, forming dense masses. This plant is 

 extensively used in the manufacture of help, and furnishes besides excellent 

 winter food for the cattle in the western islands of Scotland. See Light- 

 foot, FL Scot. vol. ii. p. 906. 



2. F. ceranoides, L.; frond plane, coriaceo-membranaceous, 

 linear, subdichotomous, entire at the margin, midribbed, 

 without vesicles ; lateral branches alternate, dichotomous, 

 multifid, level-topped ; receptacles subcylindrical, acumi- 

 nated. Grev. Alg. Brit. p. 14; Hook. Br. FL ii. p. 267 ; E. 

 Hot. t. 2115 ; Wyattj Alg. Damn. No. 153. 



Sea-shores, less common than the last. Perennial. Spring and sum- 

 mer. Nearly related to the last species, but " it is far less tough, much 

 thinner and more transparent in every part, both in the growing and the 

 dried state. The midrib is finer and more clearly defined." Grev. 



3. F. serratus, L. ; frond plane, coriaceous, linear, dicho- 

 tomous, serrated, midribbed, without air-vessels ; receptacles 

 flat, solitary, terminating the branches, serrated. Grev. Alg. 

 Brit. p. 15 ; Hook. Br. FL ii. p. 267 ; E. Bot. t. 1221 ; Wy- 

 att, Alg. Danm. No. 2 ; Harv. Phyc. Brit. t. xlvii. 



Rocky sea-shores, very common. Perennial. Spring and summer. 

 Frond 2 6 feet long, very variable in breadth, dark olive-green. This is 

 sometimes used in the manufacture of kelp, but rarely, as it is far less pro- 

 ductive than F. vesiculosus. It however forms excellent manure, and in 

 Norway it is used, mixed with meal, as provender for cattle. 



** Frond flat or compressed, without a midrib. 



4. F. nodosus, L. ; frond compressed, coriaceous, sub-di- 

 chotomous ; branches linear, somewhat pinnated, attenuated 

 at base, remotely denticulate, here and there swelling into 

 oblong air-vessels; receptacles lateral, globose, stalked, 

 springing from the axils of the serratures. Grev. Alg. Brit, 

 p. 16; Hook. Br. FL ii. p. 268 ; E. Bot. t. 570; Wyatt, Alg. 

 Danm. No. 154 ; Harv. Phyc. Brit. t. clviii. 



Sea-shores, very common. Perennial. Winter and spring. Root a, 

 large, hard, conical mass, from which spring several fronds 2 1 or even 6 

 feet long, which are once or twice forked, and irregularly pinnated with 

 alternate simple branches. Vesicles large. Substance extremely tough 

 and leathery. Colour full olive-green, glossy. 



5. F. Mackaii, Turn. ; frond cylindrical or subcompressed, 

 slender, much branched; branches dichotomous ; air-vessels 

 elliptical, solitary ; receptacles lateral, lanceolate, ovate or 



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