lower part, gradually attenuated upwards, irregularly dichotomous at longish 
intervals, and furnished more or less copiously with lateral simple, forked, 
or repeatedly dichotomous ramuli: the axils patent; the apices either 
hooked inwards or straight. Minor characters of branches excessively 
variable. Articulations opake, coated with a thick stratum of small coloured 
cells, marked (frequently) with an oval area, being an internal air-cell or 
tube, seen through the coat ; dissepiments contracted. Favelle involucrate, 
spherical, borne on the sides of lateral short ramuli. etraspores immersed 
in the substance of the articulations, several in each articulation, in a trans- 
verse line. Colour, where the plant is in perfection, a fine, deep, clear-red ; 
varying to all shades of red-brown, fulvous, yellow, and even greenish, 
down to white. Suéstance membranaceous or cartilaginous. It more or 
less perfectly adheres to paper. 
RINNE aren 
This plant, one of the most universally diffused of the Floridce, 
and one of the commonest on every shore where it grows, puts on 
so many deceptive appearances that the young botanist and even 
the experienced observer are again and again deceived by it. As it 
grows from near the limit of high water to beyond the recess of 
the tide, it is exposed to a very variable amount of solar ight and 
heat, a circumstance which at once accounts for the varieties in 
colour which the frond assumes. The variations in ramification 
depend on more hidden causes: but they are such that, however 
dissimilar different specimens may seem, other intermediate states 
may in most instances be detected which perfectly connect them. 
Still it is possible that the specific characters above given may 
apply to more than one species. I now allude to a virgate plant 
which I have hitherto regarded as a variety of C. rubrum, but 
which may ultimately, perhaps, be admitted to rank as a species, 
should a more definite character be discovered to distinguish it. 
The Ceramia are almost as unsatisfactory to the botanist as the 
Rubi; and their varieties quite as numerous. They are, how- 
ever, very beautiful plants, and thus, in some degree, the botanist 
is repaid for the trouble which their investigation often occasions. 
Fig. 1. CeRAMIUM RUBRUM :—of the natural size. 2. Ramulus with a favella. 
3. Ramulus with imbedded tetraspores. 4. Tetraspores. 5. Portion of 
the main filaments :—all magnified. 
