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 Desmidiaceag and Diatomaceae. 

 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 



