characters except in size witli liis specimens. I trust, therefore,
that in adopting the specific name I am not committing an error,
although, were I to form my judgment of C. decurrens on the
diagnosis assigned to it by its founder, I should not have referred
to it the specimens here figured.
Our C. decurrens seems to be almost exactly intermediate
between C. ruhrum and C. diaphanum. It agrees with the
former in size, but differs in having a translucent space, destitute
of colomed cells, in the middle of each internode. From C. diaphanum
it differs chiefly in having the lines of coloured cells
which clothe the nodes continued over a considerable space of
the articulation, and thus, as it were, decurrent along the stem.
The exact disposition of these cells, and the structure of the
stem, is well seen when a longitudinal slice is taken, as at fig. 4.
The minute coloured cells will then be found immersed in the
transparent walls of the frond.
I have seen no other specimens than those found at Torquay,
one of which is here figured. There is a variety of C. ruhrum
wliich I once confounded with G. decurrens, from its having a
pale or transparent band in the centre of the internode but
this variety, when examined more closely, will be found to have
the whole of its walls traversed by strings of cells, but having
those of the centre part colourless or pale.
Fig. J. Cek.amium DEOÜKEENS, S- «tajus :—ffie natural size. 3, Apex of a
branch. 3. Articulations from the middle of a branch. 4. Vertical section
of the same :— all highly magnified.