Ge n u s X V . PUNCTARIA, Grev. Tab. IX.
Ge n . Ch a r . Frond simple, membranaceous, flat, with a
naked scutate root. Fructification scattered over tbe
whole frond in minute distinct spots, composed of roundish
prominent seeds, intermixed with club-shaped filaments.
O bs. In proposing this genus, I am not without fear that the giound
of distinction may be considered too slight. The frond, however, besides
being flat, is formed of an interlacing of longitudinal and transverse filaments,
covered by a finely reticulated membrane. Aspcrococcus, on
the other hand, in addition to this structure, exhibits on the inner
surface an approximation to tlie cellulose organization of ChordaFilum.
The fructification is very similar to that of Aspcrococcus, in being accompanied
with the club-shaped filaments. It is remarkable that the
seeds of the last named genus should have been overlooked by
Agardh, who makes the generic character to rest entirely upon the
filaments or apiculi. These articulated apiculi, however, I have ascertained
to exist in the present and even in the following genus, though
in a less perfectly developed form, and I am inclined to regard them
as abortive seeds : or, in other words, as linear extensions of the cells
of the frond, with the abortive substance of the seed diffused in the
uppermost cellules.
The generic name is derived from the Latin word signifying a dot
or minute spot, the frond being covered with the dotted fructification.
I. P u n c t a r ia l a t i f o l ia .
Fi'ond naiTow-ohovate or oblong wedge-shaped.
H a b . On rocks in the sea. Annual. April and May. Sidmouth,
Mrs Griffiths. Near Belfast, Dr Drummond.
Root a very minute disk. Fronds several from the same base,
three to eight inches in height, one to two inches or more in width at
the broadest part, mostly obovate, flat, even or slightly waved at the
margin, rounded or between rounded and truncate at the top. Fructification
minutely dot-like, scattered over the whole surface, composed
of roundish seeds, intermixed with linear-elliptical, articulated, short
filaments, filled with a dark reddish mass.
Substance thin and flaccid, adhering to paper in drying. Colour
while young, a rather bright yellowish olive-green, when mature, olivaceous
brown, not changing by exposure to the air.
I have never seen any specimens of this species, except one found
by Dr Drummond, and those communicated by Mrs Griffiths, some
of which being gathered at Sidmouth during my residence there, I
had an opportunity of examining in a fresh state. In its outline and
general appearance, it resembles Laminaria debilis, which, as well as
the two following species of Punctaria, Sprengel has referred to his
Zonaria plantaginea,—an association which proves him to have generalized
without much examination.
2. P u n c t a r ia p l a n t a g in e a . Tab. IX.
Frond from linear-club-shaped to linear-lanceolate, much attenuated
at the base, subopake.
Zonaria plantaginea, S p r e n g . S p . P I . v . 4. p . 326.
Zonaria? plantaginea, A g . S p . A lg . v . 1. p . 138. S y s t. A lg . p . 268.
Ulva plantaginea, R o th . Sm . E n g . B o t. t . 2136. L y n g b . H y d r o p h . D a n . p . 31. t. 6.
H a b . in the sea, attached to rocks, stones, and the larger Algse.
Annual. Summer. Cromer, Turner- Coast of Sussex, Mr Borrer.
Falmouth, Mr G. Sowerby. Dawlish, Mr Pigott. Near Belfast,
Dr Drummond. Frith of Forth.
Root a minute disk. Fronds generally aggregated, six to twelve
inches long, three lines to nearly an inch broad in the widest part,
linear, linear-lanceolate, or linear with a slight dilatation upwards, the
apex either obtuse or somewhat acute and attenuated; the margin
slightly waved. Fructification ovate reddish green seeds in minute
scattered dots, intermixed with a few short filaments ; seeds are also
scattered singly over the whole surface. Substance thin and tender,
very often perforated to a great extent by marine animals. Colour
olivaceous or reddish brown, and rather opake.
In this species, which is undoubtedly very nearly related to the
preceding, the apiculi or little short filaments are scarcely to be
traced; while the seeds, on the other hand, are very plentiful, and
scattered over the whole frond; those forming the dots being comparatively
few in number. This fact points out the impropriety of regarding
the apiculi as essential to the generic character. The seeds
are tolerably correctly represented by Lyngbye, though he has omitted
the pellucid case. The little dots of fructification, though always