î t I V U L A R I A vermiculata.
Worm-shaped Rividaria*
CRYPTÙGAMIA Algæ.
Gèn. Char. Frond gelatinous, firm, destitute of an
external cuticle. Fructification among jointed filaments,
lodged in the substance of the frond.
S pec . C h a r * Cylindrical, much branched, brown ;
branches scattered, subdivided, Crooked. Internal
filaments compound and divaricated ; their ultimate
branches clustered, beaded, thickened upwards.
Fruit obovate, sessile at the base of the beaded
branches.
S e n t from the north-east coast of Ireland, near Lam, by
Mr. Drummond, in August 18 0 6 . The specimen in our plate
was found at Brighthelmston in July 1807, by Mr. W . Borrer.
We cannot refer it to any plant described by British writers,
who would all doubtless have reckoned it an Ulva ; neither
do we find any suitable description in Roth, to whose genus
Rivularia it must surely be referred, unless the fruit, being
separate from the filaments, should constitute a new genus,
on the principle of that ingenious author’s Ceramium. We had
rather however wait till the fruit of all the original Rivularice
are better ascertained.
The whole plant is 4 or 5 inches high, olive brown, very
much and irregularly branched, cylindrical, solid, crooked,
becoming flattish only when broken. Its whole substance is
succulent and gelatinous, the external part presenting an
assemblage of pellucid, slimy, jointed, branched filaments,
more condensed and firmly compacted in the inner part.
These filaments bear innumerable tufts or clusters of shorter
ones, jointed quite in a different manner, being thickly
beaded, or formed of globular articulations, which are moreover
gradually larger towards the extremity. At the base of
some of these beaded filaments stands an obovate pellucid
capsule, containing apparently one dark-brown seed. These
numerous capsules give the whole plant a dark hue.
Mr. Woodward’s Ulva decor ticaia,Tr. of Linn. Soc.v. 3 . 5 5 ,
may possibly belong to this genus. See that excellent observer’s
remarks.