RHODOSPERME”. 219 
found this common species most abundantly in Torbay and at Plymouth. 
Section 3, Rosea, contains some of the most lovely plants of this genus. 
The main stems of all are mostly very slender, and the joints or articu- 
lations of the branches are pellucid and very distinct. In some of the 
older plants of several species in this group the main stems are nearly 
opaque, being traversed or filled with veins or longitudinal filaments. 
In all, the ramuli are alternate, never opposite. 
C. roseum, represented the natural size at Fig. 200, is found on muddy 
rocks, and sometimes on other weeds near low-water mark, on the coast 
of Norfolk, at Brighton, and down the south coast of Devon and Cornwall. 
At Plymouth I have often found this species in the highest perfection. 
I have taken specimens there, the fronds of which were over 6in. long, 
and the colour an exquisite mixture of light purple and brilliant crimson. 
The fronds of this beautiful species ‘are excessively branched ; all the 
branches are irregularly pinnated or winged, and these pinne or winglets 
are set with wide spreading ramuli, which gradually shorten towards 
the tips, giving to the pretty plumules a graceful pyramidal outline. 
These plumules are generally so crowded in the upper branches, that they 
give a very densely feathery appearance to the outline of the plant, as 
well asa deep rosy tint to the terminal portions of the fronds. Tetra- 
spores are seated on the inner face of the ramuli, about three or four 
on the lower ones, and diminishing in number upwards, as seen 
in the magnified plumule at a, Fig, 201. Favelle are produced near 
the tips of the plumules. The joints of the stems are about three 
times, those of the ramuli about twice as long as broad. The plant 
is an annual, and is in perfection during the summer months. C. 
byssoideum, though met with in many situations, is by no means 
a common species. The fronds of this plant are extremely slender, and 
very difficult to display without mjury. They are densely branched from 
the base, and crowded throughout with lesser branches, all of which are 
clothed with very flaccid byssoid branchlets, set with slender pinnate 
ramuli, which generally shorten upwards and terminate in a fine point. 
The joints of the stem and principal branches are about six times 
longer than broad, and those of the ramuli somewhat less. Tretraspores, 
elliptical in form, are seated on the inner side of the ramuli, as seen in the 
magnified plumule at b, Fig.201. Favelle, which are sometimes three-lobed, 
are attached to the sides of the stems. This species is occasionally mis- 
taken for fine or delicate forms of C. corymbosum (Figs. 203 and 204), 
but the joints in the branches of the latter are much longer, and 
the terminal branchlets are more level-topped, each fork being tipped 
with a pair of divaricating articulations, slightly longer than broad. 
The colour is a delicate rose-pink, in early growth a rich brown-red, 
and the plant firmly adheres to paper in drying. C. polyspermum, so 
named from the abundance of its tetraspores, which are produced on the 
spreading spine-like ramuli of the lesser branches in regular closely set 
series from the base to the tip, as seen at c, Fig. 201. The globular 
