Ser. M e la n o s p e rm e .:®. Fam. Fticea.
P l a t e L I I .
FUCUS MACKAII, Tum.
Gen. Chae. Frond linear, either flat, compressed, or cylindrical, dichotomous
(rarely pinnated), coriaceous. A ir vessels, when present, innate,
simple. Receptacles either terminal, or lateral, fiUed with mncus traversed
by a net-work of jointed fibres, pierced by numerous pores,
which communicate with immersed spherical conceptacles, containing
parietal spores, or antheridia, or both. Fuous (A), i
F ucus Mackaii; frond cylindrical or subcompressed, slender, much
branched; branches diohotomous; air vessels elliptical, solitary; receptacles
lateral, lanceolate, ovate, or forked, stalked, pendulous, scattered,
near the base of the branches.
F u cus Mackaii, Turn. Hist. t. 52. Sm. E. Bot. t. ]927. Lam. Ess. p. 20.
Ag. Sp. Alg. vol. i. p. 87. Hook. El. Scot. part 2. p. 95. Grev. Alg. Br.
p. 17. Hook. Br. El. vol. ii. p. 268. Harv. in Mack. El. Hib. part 3.
p. 169. Harv. Man. p. 21. Grev. in FJigc. vol. i. p. 465.
F u cus nodosus, y. Mackaii, Ag. Syst. p. 275.
P hy soca ulon Mackaii, Kiitz. Phyc. Gen. p . 3 5 2 .
H ab. Muddy sea shores, usually in land-locked bays, and among boulders.
Perennial. April and May. B irterbui Bay, Cunnemara, Mr. J . T.
Mackay. (1805). Loch Seaforth, Lord Seaforth. Aiasaig, Mr.
Borrer. Loch Coul and Kyle Scough, Sutherland, Messrs. Borrer
and Hooker. E a st coast of Skye, and head of Loch Duich Messrs.
Hooker and Greville.
G e o g k . D is t b . N o r th o f E u ro p e . B a ltic sea, Areschoug.
D e s c e . Eronds growing in globular tufts the size of a human head or lai'ger,
many fronds radiating from a subcentral point, but without obvious root or attachment.
, Eronds 6-12 inches long, from half a line to two lines in diameter,
cylindrical or subcompressed, cartilagineo-coriaceous, rather brittle, ribless,
with a short, simple or forked main stem, from which issue, without much
regularity, numerous long, repeatedly dichotomous or occasionally trichoto-
mous branches, which graduafiy taper to the apices, where they are often
less than a quarter of a line in diameter, and are beset throughout their
length with more or less frequent, lateral, simple, or forked, patent ramuli.
Axils patent, rounded; apices blunt. Vesicles from a quarter to half an
inch in length, two lines wide, few, ocourring generaUy below the forkings
of the longer branches; sometimes wanting. Bxceptacles lateral, borne by
slender peduncles issuing irregularly from the sides of the branches near
their base, pendulous, lanceolate, or hilobed, or somewhat ovate, yeUow,
containing numerous spherical conceptacles, fuU of roundish spores, each of
which separates at maturity into four sporules. Colour a d u l olive. Sub-
I when dry somewhat horny and translucent.
O 2