t r
H. ti
Hitherto this plant has appeared in British works as a variety
of S. rhizodes, figured at Plate LXX, and notwithstanding its
different appearance, when typical specimens of each are under
examination, it is not without hesitation that I admit the present
to be specifically distinct. Those who are acquainted with the
difference in aspect assumed by marine plants, according to the
depth of water at which they grow, will best understand my
doubts; remembering that the typical 8. rhizodes grows within
tide-marks, and 8. Lynghymi at a considerable depth, beyond the
reach of the tide. And the differences between the two are precisely
of the nature of those caused by deep water. If we regard
size, we must remember that Asperococcus Turneri in tide pools
is seldom more than six inches long; and that when growing
with our 8. Lyngbymi, which it frequently accompanies, it has
fronds three or four feet in length and proportionahly broad.
So also Graoilaria confervoides, which grows to six or seven feet
in length in deep water. The distention of the frond in 8tilo-
phora and the attenuation of the branches likewise increase with
depth. On the whole, therefore, the characters typical of our
8. Lgngbycei become more strongly marked as the depth of water
increases, and appear to me greatly to depend on locality. It is
for this reason that I am inclined to question its right to be considered
a species, distinct from 8. rhizodes.
r Fig. 1. S t i l o p h o e a l y n g b y æ i ;—part of a frond, the natural size. 3. Segment
of a branch. 3. Cross section of the same. 4. Section of a wart. 5. Spore
and paranemata, from the same ;— all i