OF THE HERBARIUM. 
187 
botanist, to retain the original label, i.e. the one sent with 
it ; if, however, the name employed by the giver differs 
from that in the system after which the student arranges 
his own herbarium, then let him add a second label with 
the necessary information. 
It frequently happens with some of the Alga*, that the 
species gathered are irretrievably mingled together, so that 
it is hopeless attempting to separate them : this is more 
particularly the case with the Desmidiacese and Diatomacese. 
If the collector has sufficient material, he should proceed to 
make as many preparations as there are species in the 
gathering, introduce them into their proper places, and 
ticket them accordingly. For instance, we will suppose, 
that there have been taken at one gathering specimens of 
Gomphonema, Pinnularia, Meridion, Synedra, Fragilaria, 
and Closterium. Should he not be able to separate them 
satisfactorily, let him make six different preparations, each 
containing examples of the several genera. Next let him 
inscribe one label with the Gomphonema species, another 
with the Pinnularia, &c., and arrange them in his herbarium 
as though the species denoted by the ticket were the only 
one present in that preparation. 
When, however, the gathering is too small in quantity 
to allow of dividing it in this manner, he must make a 
single preparation, but place labels, corresponding to the 
number of species in the preparation, in their respective 
■wrappers. Thus, taking the last-named illustration, the 
preparation will occupy the wrapper apportioned (we will 
say) to Gomphonema ; the others, Pinnularia, Synedra, 
&c., will be represented in their wrappers by tickets, labelled 
with their names, and referring the reader to the Gom- 
phonema preparation. 
I strongly recommend the student not to be satisfied with 
solitary examples of plants from a single habitat. The 
delicate shadings and variations, due to differences of 
situation, soil, and climate, cannot be rightly appreciated, 
until the observer has before him an abundant supply of 
