acute point. Barren specimens and those which produce tetraspores, have
the forked branches usually naked; in tubercle-bearing individuals, on the
contrary, they are pinnated with short, horizontal, simple or forked ramuli,
two to three lines long. Tubercles borne on the ramuli, either at their
apices or more commonly below the point, which projects like a horn, solitary,
or two or more together, usually very abundantly produced. Tetraspores
contained in dark coloui-ed swellings of the branches immersed in the
substance ; each sorus of large size, thick, containing innumerable chained
cruciate tetraspores. Substance cartilaginous, shrinking very much in drying.
Colour, a dull purplish or brownish-red. I t does not adhere to paper in
drying, unless after long steeping in fresh water.
For splendid specimens, fresh from the sea, of this very rare
Alga, I am indebted to Mr. Gilbert Sanders of Plymouth, who
was so fortunate, towards the close of last year, as to re-discover
an old habitat where the plant had been sought for many years,
and not found since 1829. From one of Mr. Sanders’ newly
gathered specimens our figure has been taken.
The characters of this species are so strongly marked, especially
when in tubercular fruit, as is commonly the case, that it
can scarcely be mistaken for anything else. In habit G. mammil-
losa comes nearest to it, but the channelled frond of that species
affords a sufficient character. Barren specimens, or specimens
with tetrasporic fruit, have rather the aspect of very narrow individuals
of Chondrus crispus, but they seldom occur except in
company with unmistakable forms.
All the specimens received from Mr. Sanders bore tubercles.
I have since been favoured by Dr. Cocks, with specimens well
furnished with tetraspores. The latter are contained in very
dense sori, something resembling nemathecia, sunk in the substance
of the frond.
Fig. 1, G ig a e t in a p is t il l a t a -.— o f tie natural size. 2. Part of a branch
with fertile ramuli. 3, Section of a tubercle. 4. Spores from the same.
5. Section of a sorus. 6. Tetraspores from tte same. 7. Transverse
‘>®™-®“ tion of a smaU portion of the frond -.— all more or less highly mag