20 FUCUS HIMANTHALIA. 



forked, pendulous, scattered, near the base of the branches. 

 Grev. Alg. Brit. p. 7 ; Hook. Br. Fl. ii. p. 268 ; E. Bat. t. 

 1927 ; Harv. Phyc. Brit. t. lii. 



Muddy sea-shores, usually in land-locked bays, and among boulders. 

 Perennial. April and May. West of Ireland and north and west of Scot- 

 land. Frond 610 inches long, densely tufted, branches crowded, spread- 

 ing compressed at base, cylindrical upwards. Vesicles wider than the 

 frond. Substance leathery", when dry somewhat horny. Colour dull 

 olive-green. 



6. F. canaliculatus, L. ; frond coriaceous, linear, channel- 

 led on one side, dichotomous, without air-vessels ; recepta- 

 cles terminal, oblong-wedge-shaped, swollen, bipartite. Grev. 

 Alg. Brit. p. 18; Hook. Br. Fl. ii. p. 268; E. Bot. t. 823 ; 

 Wyatt, Alg. Danm. No. 102; Harv. Phyc. Brit. t. 



Rocky coasts, near high-water mark. Perennial. Summer and autumn. 

 Frond 26 inches high, densely tufted, several times dichotomous, of an 

 olive-brown or yellowish colour. 



VI. HIMANTHALIA. Lyngb. [Plate 2, B.] 



Frond top-shaped. Receptacles very long, strap-shaped, 

 repeatedly forked, springing from the centre of the frond, 

 filled with mucus traversed by jointed fibres, and pierced by 

 numerous pores, which communicate with immersed, spheri- 

 cal conceptacles, containing either parietal spores or anthe- 

 ridia. Name, from //waj, a strap, and flaAoj, a branch, or AJ, 

 the sea ; a translation of the common English name " sea- 

 thongs ." 



1. H. lorea, Lyngb. ; frond top-shaped, at length collapsing, 

 plano-concave, stalked ; receptacles repeatedly dichotomous, 

 linear, slightly tapering at the extremity. Grev. Alg. Brit. p. 

 20. t. 3 ; Hook. Br. Ft. ii. p. 269 ; E. Bot. t. 569 ; Wyatt, 

 Alg. Danm. No. 3. 



Rocky sea-shores, common. Biennial. Winter and spring. Fronds 

 gregarious, about an inch high; receptacles 2 10 feet long, coriaceous, 

 thong-like, dark olive-green. Authors are at variance as to the duration 

 of this plant, and also as to the name properly applicable to the long, 

 branching part, here called a receptacle. From recent observations I have 

 no doubt that this plant is biennial ; and its development, I think, justifies 

 the views here adopted as to the nature of its several parts. It is a com- 

 mon habit of biennial plants to spend the first year in perfecting the 

 organs of vegetation, and to start into fruit in the following season. This 

 is exactly what takes place in this sea-weed. The top-shaped, or finally 

 cup-shaped base which is here called a frond, but which in the view of 

 some authors is a vesicle, takes a whole year to arrive at perfection, and 

 is fully formed before any part of the strap-shaped receptacle makes its 



