twice as long as broad.' Colour a brownish-red, pui-plish when dry.
Substance between cartilaginous and membanaceous, adhering to paper.
I here figure a plant which in the ‘ British Flora ’ I had incorrectly
referred to C. granulatum, Ag., a species which I
now know to he much more nearly allied to our C. spongiosum.
In the ‘ Manual I have been content to regard the present as
merely a slender variety of C. tetragonum, with which it is very
commonly confounded, and which it resembles in most of its
essential characters, and in general aspect can hardly be distinguished,
except on a close inspection. My friend Professor J.
Agardh, however, has judged differently, and done me the honor
of giving it my name, in which he has been followed by Endh-
cher, in his useful Synopsis. My attention is thus again directed
to the subject, and I have deemed it best to give a figure in
which all the characters by which it differs from C. tetragonum
being depicted, botanists may form their own opinion as to the
validity of its claims to rank as a species. I should have adopted
the specific name of Agardh, had I not received from M. Lenormand
specimens, exactly similar to our British ones, bearing a
name conferred by Bonnemaison, which, I believe, has priority
to that proposed by Agardh, though at present I am not aware
where it has been published.
The character by which C. bracMatum appears essentiallg to
differ from C. tetragonum, is to he found in the ultimate ramuli,
which in this are constantly subulate, gradually tapering from the
base to the apex ; and in that are suddenly acuminate, or, as
it were, mucronate. This is what originally induced me to admit
the species, which I found indicated in the unpubhshed ‘ Algse
Appinenses ’ of Carmichael, under the name C. fruticulosum ; and
so far as my observations have gone, this character appears to be
constant. Minor and less important distinctions may be taken
from the length of the joints, and their form, which is cylindrical
in the present species and oval in C. tetragonum. Both plants
are equally common, and found in the same situations.
Fig. 1. Callithamnion bbachiatum :— of the natural size. 2. Penultimate
branches. 3. A plumule, hearing tetraspores. 4. Apex of a fertile pini‘
1
nule. 5. A plumule hearing a favella,
the stem :— all
6. Joint of a main branch or of