A very distinct and beautiful species of this charming genus, 
and one which is very widely distributed. It was first noticed 
in the Mediterranean, from whence I have received excellent 
specimens. Mrs. Griffiths added it to the British Flora nearly 
twenty years ago; and it has since been found on several parts 
of the English and Inish coasts. More recently Mr. Gunn has 
sent specimens from Tasmania exactly similar to our European 
plant, thus proving that it exists in the temperate regions of the 
Southern, as well as of the Northern Hemisphere. It is not 
subject to much variation, except of a very minor character. 
The opposite or quaternate pinnulated ramuli constantly mark it. 
In some individuals the jomts of the stem are much shorter, the 
ramuli more dense, and the whole plant very small. These, 
before I was well acquainted with the variations of C. cruciatum, 
I was disposed to regard as a distinct species, which I described 
under the name of pumilum, mn the British Flora. A better 
acquaintance with the species has shown that this view cannot 
be maintained. I have specimens from Torquay showing every 
gradation between the original pumilum and the normal state of 
the plant; and I have others which vary in an opposite direction 
—the joints being very long, and the ramuli distant and either - 
simple or with very few pinnule. Such specimens show an ap- 
proach to the rare C. floccosum, though abundantly different from 
any state of that beautiful plant. An excellent mark for C. 
cruciatum, by which it may be known at a glance, hes in the 
very dense tufts terminating the branches, consisting of unde- 
veloped ramuli. 
Fig. 1. CALLITHAMNION cRUCTATUM; a tuft :—of the natural size. 2. Part of 
a branch, clothed with ramuli. 3. Portion, with fertile ramuli. 4. Tetra- 
spores, in situ. 5. Uppermost pinnule :—all more or less highly magnified. 
