THE BROWN SEAWEEDS OF THE SALT MARSH. 353. 
(0) Head cespitosus. 
Habit turfy, generally 3-6 ems. high and 1 mm. broad, membranaceous, 
dichotomously branched, slightly or not at all spirally twisted, midrib 
indistinct. — Cryptostomata prominent, marginal. Air- vesicles absent. 
Receptacles very rare, terminal, spherical or ovoid, simple or bifid, 5-8 mm. in 
length.  Diœcious ; oogonia dividing into oospheres. 
Hab. In the upper flats of peaty or muddy salt marshes. Coasts of Essex : 
Blackwater Estuary; Blakeney, Norfolk ; Hurst Castle, Hants ; Northum- 
berland; Berwick ; Argyle; Firth of Lorne; Renfrew, Gourock ; Wemyss 
Вау; Loch Linnhe; Bute ; Arran ; Cumbrae ; Mochras, Carnarvon ;. 
Arcachon in France. 
Fucus vesiculosus v. subecostatus, Harvey, Phye. Brit, vol. i. pl. 24; Greville, 
Alg. Britt. (Edinburgh, 1830) p. 12. 
Fucus vesiculosus v. balticus (non J. Ag.) ; Hooker’s British Flora, по. 267, 
and Куз. Batters, “ Marine Algæ of Berwick-on-Tweed” : in Berwick- 
shire Nat. Club Trans. 1889, р. 84. Batters, in Journ. Bot. xl. (1902) 
Suppl. p. 50. Receptacles described : Cotton, in Proc. Roy. Irish Acad. 
xxxi. рр. 125-126. 
Fucus balticus: vs. Mrs. Griffiths, ete. 
Fucus lutarius v. arcassonensis? Sauvageau, in Soc. Biol. Bordeaux, 1908, 
fig. 20, p. 181. 
(c) Eead muscoides (Cotton). 
Plants very short, fastigiately branched, densely crowded together, 
5-6 ems. long. Branches cylindrical or compressed, 1-3 mm. wide, not 
twisted, with marginal eryptostomata. Receptacles very scarce, minute, 
9-4 mm. diameter. Dicecious ; paraphyses not projecting. 
{ Hab. On firm peaty salt marshes as a dense mossy turf. Roundstone and 
Clew Bay, Ireland ; Loch Linnhe, W. Scotland. 
Fucus vesiculosus v. muscoides, Cotton, in Proc. Roy. Irish Acad. xxxi. 
(1912) p. 127, pl. 6. figs. 1 & 2. 
Section B. Loose-lying forms. 
Thallus free; branching densely fastigiate and radial. No spirality. 
Fucus balticus, Kitz. Tab. Phyc. x. Taf. 12; Gobi, Brauntange, р. 19, 
Taf. 2, figs. 19-22 ; non Ag. in Svensk Bot. tab. 516. 
Fucus vesiculosus v. balticus, J. Ag. Spec. Alg. i. р. 210. Hus. J. E. 
Areschoug, Alg. Scand. ; Rabenhor st, Krypt.- Flor. v. Deutsch. ii. p. 291. 
(d) Ecad nanus (Ag.). 
Margins of thallus waved and folded. Cryptostomata indistinct or absent, 
leading from dwarf forms 2-5 ems. in length to the attached f. plicata, 
Kjellm. Always sterile. 
