shade. Substance very soft, in some instances gelatinous, and soon decom- 
posing in fresh water. Smell very disagreeable. 
This is one of the handsomest, as it is one of the largest 
of the British species of Polysiphonia, and easily recognised, 
except occasionally from some specimens of P. fruticulosa, 
by its peculiar habit. The inarticulate stem, and long, simple, 
robust branches clothed with pencils of delicate filaments strongly 
mark the species. Common as it is now ascertained to be on 
many of our shores, as well as on those of northern Europe and 
the eastern shores of North America, it remained unnoticed 
by botanists until it was observed about forty years ago, by the 
late Mr. Brodie, of Brodie, to whose honour Mr. Dillwyn has 
dedicated it. 
The figure origmally given in Dillwyn’s Confervee is very 
characteristic of a common form of the plant ; and so also, as it ap- 
pears to me, is that given by Lyngbye, which latter, nevertheless, 
is held by the elder Agardh to represent a distinct species, which 
he calls P. penicillata. Except in the greater simplicity of rami- 
fication, this last perfectly agrees with the common form; and 
I confess myself unable to draw any distinct line, even sufficient 
to mark a variety, between it and the plant represented in our 
plate. It would be easy to find, in the large suite of specimens 
from which I have had to select, several forms distinguished by 
minor peculiarities of branching, which nevertheless agree in the 
ageregate of characters; and if P. penicillata be admitted to 
rank as a species, we must be prepared to divide the species 
still more; but, I think, to little purpose. 
Fig. 1. PotystpHonta Bropimi:—of the natural size. 2. Multifid ramulus, 
with capsules. 3. Apex of the same, with a capsule. 4. Apex of a ramulus 
with tetraspores. 5. Transverse section of the stem. 
