CHLOROSPERME®. 17 
C. rupestris (b, Fig. 21) or the Rock cladophora. It is easily recognised by 
its very dark or blackish-green colour, and by the excessive rigidity of its 
filaments, and erect ramuli or branchlets. This species does not readily 
adhere to paper. Therefore, 
the best way in preparing it 
for the herbarium is to mount 
it on paper in the usual man- 
ner in sea water, and after it 
is partially pressed and nearly 
dry, to immerse it, paper and 
all, in skimmed milk, and 
then dry and press it as 
before, after which it will 
adhere closely to the paper 
for an indefinite period. 
To general observers, many 
of the Cladophora look won- 
derfully alike, all of them 
Fie. 17. Cladophora rectangularia. 
Fie. 18. Cladophora falcata, being more or less bushy and 
Fie. 19, Vaucheria velutina (ramuli with excessively branched, and 
vesicles). 
green of various shades being 
the prevailing colour; but as the tints vary greatly, according to the age of 
the plants and the situation in which they grow, even in individuals of the 
same species, colour is by no means a character which can be implicitly 
relied on. An examination of at least terminal branchlets with a good 
lens is absolutely neces- 
sary, and thus they will 
all be found to be more 
or less abundantly dif- 
ferent. I have selected 
a few species, which are 
most likely to be met 
with, in illustration of 
my remarks, and because 
I think that my figures 
of magnified branches 
will help students to 
distinguish their charac- 
teristic ramification or 
mode of growth, and the 
peculiarity of branching, 
as well as the differ- 
ences in the form and 
size of the articulations in the terminal ramuli or branchlets. The 
illustration of the species Cladophora arcta (Fig. 20, and c, Fig. 21) is not 
only highly characteristic of this plant, which invariably: presents a 
C 
Fie. 20. Cladophora arcta. 
