dinensia” to have heen discovered by Captain Carmichael, and a
representation is given of it from one of that gentleman’s drawings.
I have in vain searched for the same appearance. Captain Carmichael
does not mention whether the two kinds occur on distinct individuals.
The structure of the frond is extremely singular. The naturalist
last mentioned expresses himself happily when he observes, that the
frond is composed of a “ simple fillet, one or two lines in breadth,
spirally twisted into a filiform tube, formed by the cohesion of its
edges.” Any one may prove this to his own satisfaction, hy inserting
a probe at the base, and carrying it along the interior of the frond.
When in fall fructification the frond is liable to become inflated and
distorted, and is more than usually gelatinous.
The Scytosiphon fstulosiim of Lyngbye, which Agardh makes a
variety of C. Filum, I consider to be nothing more than Aspcrococcus
echinatus in a ban-en state.
Chorda Filum is used in Norway as food for cattle.
tS'l
2 . C h o r d a l o m e n t a r i a .
Frond membranaceous, the transverse septa remote and at irregular
intervals, accompanied with an external constriction, the intervals
somewhat inflated.
Chorda Lomentaria, L y n g b . H y d r o p h . D a n . p . 74. t . 18.
Scytosiphon filum, v a r . y , Ag. S p . A lg . v . 1. p . 162. S y s t. A lg . p . 257.
H ab . In the sea, on rocks and stones. Annual. Summer and
autumn. Frequent. Devonshire very plentiful, Mrs Griffiths. Near
Belfast, Dr Drummond. Abundant both on the western ami eastern
coasts of Scotland.
Root a minute disk. Fronds several from the same base, three to
sixteen inches in height, one to four lines in diameter in the middle,
attenuated at each extremity, but especially at the base, hollow, contracted
at the articulations to half its diameter or more; the spaces
between the contractions very unequal, from half an inch to two inches,
more or less inflated. Fructification (as far as I have been able to
discover) interrupted masses of minute cylindrical or somewhat club-
shaped jointed filaments.
Substance thin flaccid and membranaceous, adhering to paper in
drying. Colour somewhat transparent yellowish olive green, scarcely
becoming darker when dried.
A careful examination of this plant induces me to think it a very
distinct species. From its membranaceous substance, I have been
accustomed to consider it a species of Aspcrococcus, if not a variety of
A. echinatus. But the total absence of the fi-uctification of that genus
led me to study it more closely. The frond is really divided by transverse
septa, and the substance is composed of lax cells, as in Chorda
Filum, with which it also agrees in having to a certain extent a spiral
structure. The surface is covered with interrupted masses of very
minute club-shaped filaments, fixed by their base; but they are hardly
moniliform, as represented by Lyngbye. The most curious circumstance
attending them is, that they are in pairs, each pair being connected
by their base. Some farther facts doubtless remain to be discovered
concerning the fructification of this species.
The appearance of the plant is very similar to the intestine of an
animal tied at certain intervals.
ill.
G e n u s XIV. ASPEROCOCCUS, Lamour. Tab. IX.
G e n . C h a r . Frond tubular, cylindrical, continuous, membranaceous.
Root minutely scutate, naked. Fructification,
distinct spots composed of imbedded seeds, mixed
with erect club-sliaped filaments.
O b s . This very natural genus was created by Lamouroux expressly
for a plant which he erroneously conjectured to be the IJlva rugosa of
Linnæus [Fuctis rugosus. Turn.) Lamouroux’s plant, however, which
is the Ulva rugosa of De Candolle, remains the type of the genus,
which Agardh has since called Encoelium. The name bestowed by
Lamouroux is remarkably characteristic, being expressive of the perceptible
roughness which the fructification gives to the surface of the
frond. In cases of this kind, I feel assured that Professor Agardh will
not believe me to be actuated by caprice, in preferring the original appellation.
The genus contains only four species ; for Agardh has placed his
Encoelium sinuosum and clathraium, along with Conferva crinita of
Roth, in a new genus which he names Stilophora.