r
il ' ■
mucus passing through the pores in abundance; after maturity, the receptacles
change colour and decay. On the surface of the frond in
many species, are minute pores, from which issue little tufts of white
filaments, the use of which has not been discovered. In all the species
the root is in the form of a hard disk.
* Frond plane, with a midrib.
I. F u cu s VESICULOSUS. Tab. II.
Frond plane linear dichotomous entire at the margin, air-vessels
roundish-oval in pairs, receptacles mostly elliptical terminating tbe
branches.
Fucxis vesiculosus, L in n . S p . P I . p . 1626. S t a c k h . N e r . B r i t . t. 2 . T u m . S y n . F u c . p . I I 7.
H i s t . t . 88. L am o u r . E s s a i, p . 18. Sm . E n g . B o t 1. 1066. L y n g b . H y d r o p h . D a n . p . 3.
t . 1. A g . S p . A lg . V. 1. p . 87. S y s t A lg . p . 275. G r e v . F I . E d in . p . 283. C r y p t . F li
t 319. S p r e n g . S p . P I . v . 4. p . 315.
Fucus divaricatus, L in n . S p . P I . p . 1627- L ig h t . F I . S c o t p . 909.
Fucus infiatus, L in n . S p . P I . p . 1627- L ig h t . F I . S c o t p . 910.
Fucus spiralis, L in n . S p . P I . p . 1627. S to c k h . N e r . B r i t t. 5. S m . E n g . B o t. t . 1685.
Fucus volubilis, H u d s . F I . A n g l. p . 577.
Fueus angustifolius. W i th . B o t. A r r . E d . 6. v . 4. p . 109.
Fucus Sherardi, S t a c k h . N e r . B r i t . 1 . 13.
Fucus linearis, H u d s . F I . A n g l. p . 578.
Fucus distichus, L ig h t f . F I . S c o t p . 912.
V a r . subecostatus, d e n s e ly t u f t e d , o n e o r tw o in c h e s in h e ig h t , m id r ib in d i s t in c t , n o
r e c e p ta c le s o r ,v e s ic le s , A g . S p . A lg . v . 1. p . 92.
Fucus Balticus, Ag . S v . B o t t 516. G re v . C r y p t F I . t 181.
H a b . Sea-Shores. Perennial. Summer and autumn. Very common
every where. Var. /3, in salt-marshes only occasionally flooded
by the sea. Near Dunstaffhich Castle, and on the Island of Kerera,
Mr Maughan. Appin, Captain Carmichael. Isle of Arran, Hooker.
Isle of Bute, near Point-House.
Root a hai'd fiattish disk. Frond a few inches to three or more
feet in length, and two or three lines to an inch in width, flat, furnished
with a midrib, occasionally twisted in a spiral manner, repeatedly
dichotomous, the angles of the dichotomies acute, except when a soli-
tai'y vesicle happens to be placed there: the sterile branches obtuse,
and often notched at the extremity. Air-vessels from the size of a pea
to a hazel-nut, in pairs, and situated at irregular intervals, in different
parts of the frond : sometimes two or three pair are arranged close to
each other. They are rarely altogether wanting. Receptacles terminal,
compressed, mostly ovate or elliptical, and about half an inch long,
but varying from nearly spherical to linear-lanceolate, and in length
from a quarter of an inch to nearly two inches: they are also mostly
in pairs, but are sometimes solitary, and occasionally forked. The
whole frond is proliferous in a remarkable degree in cases of injury,
throwing out numerous new shoots from the injured part.
The variety /3, is not more than one or two inches high, half a line
to one line wide, obscurely midribbed. It is only twice or thrice divided,
erect, and densely crowded, forming extensive masses among
the herbage peculiar to salt-marshes.
Substance thickish, flexible, very tough. Colour dark olivaceous
glossy green, paler at the extremities : in var. /3, tawny-yellow. In
drying it becomes blackish, and does not adhere to paper.
I find most of the varieties of this species running so insensibly into
each other, that I have ceased to consider them as capable of being
strictly defined. Even the var. /3. is rather an extraordinary state than
any thing else, depending chiefly on negative characters. When Marine
Algæ were less understood, many trifling appearances were considered
to be of importance, which are now regarded in their proper light.
Among such instances may be enumerated the twisting of the frond,
and the occasional inflation of the frond, which is nothing more than
an accidental accumulation of air between the two membranes or coats,
often distending a portion of the frond for the space of two inches or
more. Upon these circumstances two of the Linnean species depend.
In regard to the form of the receptacles, it may be observed, that they
differ even on the same individual ; and that they are rarely so constant
as to deserve separation. Most of the many appearances remarked in
this species, are caused by the influence of locality.
This plant is the common Sea Ware or Sea Wrack of the English :
the Kelp Ware and Black Tang of the Scots. It is applied to many
uses, but is chiefly employed in the making of kelp, upon which indeed
depends the value of many estates in the Western Islands of
Scotland. It serves as winter food for the cattle, which come regularly
down to the shore at ebb-tide, in search of it. The inhabitants
of Gothland, according to Linnæus, boil it, and, after adding a little
coarse flour, give it to their hogs, and consequently know it by the name
of Swintang or Stoine-tang. The dried frond is used for fuel in several
parts of. the north ; and in the Hebrides, cheeses are covered with
the ashes, and in this manner dried without salt. The ashes, in fact,
are said to contain half their weight of alkaline salt.