Himanthalia.} ALG.E MELANOSPERME/E. 169 



On the eastern shores. Belfast Lough ; Wicklow, &c. More mera- 

 branaceous than the preceding, and apparently very different ; yet I 

 am by no means convinced that this is specifically distinct. Though it 

 does not produce regular vesicles, I have frequently seen the mem- 

 branes of the frond become separated and irregularly vesicated, giving 

 the branches a blistered appearance. 



3. F. serratus, Linn. Serrated Fucus. Frond coriaceous* 

 flat, dichotomous, with a central rib, serrated ; vesicles none ; 

 receptacles solitary, terminal, plane, serrated. Hook. Br. Fl. 

 v.ii. p. 267. E. Bot. t. 1221. 



Kocky shores, abundant. 



4. F. nodosus, Linn. Knotted Fucus. Frond compressed, 

 subdichotomous, somewhat pinnately branched ; vesicles large, 

 remote; receptacles lateral, distichous, pedunculate. Hook. 

 Br. FL v. ii. p. 268. E. Bot. t. 570. 



Rocky shores, abundant. 



5. F. Mackaii, Turn. Mackays Fucus. Frond compresso- 

 cylindrical, excessively branched, subdichotomous, coriaceous; 

 vesicles elliptical (often wanting), receptacles unknown. Hook. 

 Br. FL v. ii. p. 268. E. Bot. t. 1927. 



Sea-shores. Cunnamara ; J. T. Mackay. A very remarkable 

 looking plant, yet I fear scarcely specifically distinct from the pre- 

 ceding. 



6. F. canal iculatus, Linn. Channelled Fucus. Frond li- 

 near, narrow, channelled, dichotomous, without midrib or vesi- 

 cles; receptacles terminal, oblong, turgid. Hook. Br. Fl. v. ii. 

 p. 268. E. Bot. t. 823. 



Rocky shores, abundant. The smallest of the British species, and 

 easily distinguished by its channelled fronds. 



7. F. tubercutattts, Hucls. Tuberculated Fucus. Frond cy- 

 lindrical, naked below, dichotomous above, the axils obtuse ; 

 vesicles elliptical at the base of the receptacles (often absent) ; 

 receptacles elongated, cylindrical, terminal. Hook. Br. FL v. ii. 

 p. 269. Turn. Hist. Fuc. t. 7. 



Rocky shores, rather rare. North of Ireland ; Dr. Scott. Bantry 

 bay ; Miss Hutckins. Very abundant on the west of the County of 

 Clare. Root accompanied by creeping fibres. The vesicles, which 

 have not been noticed by preceding authors, are abundantly produced 

 in the West of Ireland, where this plant is very common, ana reaches 

 a large size. 



4. HIMANTHALIA. Lyngb. Himanthalia. 



Frond coriaceous, orbicular, peziziform. Vesicles none. Re- 

 ceptacles (frond-like), elongated, strap-shaped, compressed, 

 dichotomously divided, springing from the centre of the frond, 

 containing immersed tubercles furnished with a pore. Grev. 

 Name ; //(?, WTO*, a strap, and a\s, the sea. 



x 



