O r d e r I I I .— L A M IN A R IE Æ .
Plaids all marine, o f an olive-brown or olive-green colour, becoming
someichat darker on exposure to the air ; varying from
coriaceous to membranaceous. P rm d with a lobed or fibrous
root, more or less stipitate, and, forming a plane, entire or cleft
expansion, in a few cases furnished with one or more ribs.
Vesicles none, except in the genus Macrocyst us, unless the
hollow stem o f some species be considered as such. Pructifi-
raticm, as fa r as hitherto known, either seeds mixed with a
mass o f vertical jointed filaments, or roundish granules without
filaments, fonning in both cases dense spreading spots or
sori on the surface o f some part o f the frond. Structure densely
fibroso-cellular, without any appearance o f reticulation.
This family of Algæ is proposed hy M. Bory de St Vincent, in the ninth
volume of the Dictionaire Classique d’Histoire Naturelle, p. 191.,
under the name here adopted. He is home out in this arrangement,
not only hy the fructification, but hy the structure and habit of
the group under consideration. The fructification is never tubercular,
nor are the seeds surrounded by a pellucid border. The largest known
Algoe belong to this family, and they are fixed to the rocks by a more
powerful apparatus than the simple scutate base of the F u co id eæ .
By means of thick clasping fibres, they take so firm a hold as to resist
the force of the waves ; and even specimens of a very moderate size
cannot be wrenched fiom their situation by the utmost efforts of the
botanist.
The frond is flat, and characterized by its large expansion ; it tears
in some given direction, and, under a moderate magnifying power, appears
to be of a dense uniform organization ; hut when cai-efully examined,
is seen to be constructed of a tissue of densely interwoven filaments,
and an interstitial granular mass.
G e n u s VII. ALARIA, Grev. Tab. IV.
G e n . C h a r . Frond membranaceous, furnished with a per-
current cartilaginous midrib, the stem pinnated with distinct
leaflets. Fructification, pyriform seeds, vertically
arranged in the incrassated leaflets.
The individuals which constitute this genus I have removed Ifom
an assemblage published by Bory de St Vincent, under the name of
Agarum. They are peculiar in the distichous fertile leaflets of the
stem : in the membranaceous substance of the frond, which, moreover,
differs in structure from other L a m i n a r i e æ . It is easily lacerated,
and the lacerations take place in an oblique direction from the margin
to the midrib. The surface is scattered over with minute pores, from
which issue minute tufts of filaments. The Agarum Delisei and
Pylaii of Bory belong to this genus.
The generic name is expressive of the winged frond.
1. A l a r ia e s c u l e n t a . Tab. IV.
Frond elongated ensiform entire at the margin, the stem closely
pinnated for a short space midway between the root and the frond
with linear-oblong leaflets.
Agarum esculentum, B o ry , D ie t. C la s s . d ’H is t. N a t . v . 9. p . 194.
Laminaria esculenta, L y n g b . H y d r o p h . D a n . p . 23. A g . S p . A lg . v . I . p . 110. S y s t. A lg .
p . 269. G r e v . F I. E d in . p . 282. L a P y la ie , A n n a l. d e s S c . N a t . v . 4. p . 178. t . 9. f. D - F .
S p r e n g . S p . P I. v . 4. p . 326.
Fucus esculentus, L in n . S y s t. N a t . p . 718. T u r n . S y n . F u c . p . 104. H i s t . F u c . t . I I 7 .
S m . E n g . B o t. 1. 1759.
H a b . In the sea, generally in deep water. Annual. Winter and
spring. Lizard Point, Kynance Cove, and Tintagel Castle, Mr E.
Forster junior. King’s Cove and St Michael’s Mount, rtirwen Coast
of Cumberland, Hudson. Coast of Anglesea and Isle of Man, Rev-
H. Davies. Weymouth, Stackhouse. Shores of Durham and Northumberland,
Winch- Common on the coast of Antrim, Dr Drummond.
Coast of Scotland, not uncommon, Fightfoot. Orkney, Rev.
C. Clouston. Dunbar. Isle of May, and at Seafield Rocks, on the
coast of Fife.
Root composed of thick hard simple or branched fibres, an inch in
length or more. Stem as thick as a small goose-quill, four to eight :lG: