2i 4 POPULAR SCIENCE MONTHLY. 



often has had two or more related species under his eye when describ- 

 ing the one to which he gave recognition and a name, and herbarium 

 study calls for some discriminating power; but notwithstanding the 

 inherent difficulties, its value is real and lasting. Though the founder 

 of the Missouri Botanical Garden did not specifically mention a 

 herbarium in his will, his purchase of the Bernhardi collection in the 

 early years of his planning shows his practical appreciation of the need 

 of such a part of the equipment of the institution, and in some manu- 

 script suggestions for his trustees, not made a part of his will, he 

 distinctly states that the correct naming of the plants cultivated in 

 an educational and research garden 'can only be done by a botanist, 

 aided by an herbarium and botanic library'; and one of the world's 

 greatest botanists, in speaking of the relative value of living collections 

 and the hortus siccus or herbarium, expresses himself as follows:* 

 "If the collections of dried plants are compared with those of living 

 plants, the advantages of each are more nearly balanced than is usually 

 thought. In a herbarium you see simultaneously specimens of related 

 species and also different localities, different ages or different condi- 

 tions of the same species. You know the name of the plant, if the 

 herbarium is well determined, and you go at once to the authors who 

 have spoken of it. You learn its origin, which is indicated on the 

 label. On its side, the living plant gives more means for certain 

 anatomical observations. It permits one to better describe certain 

 characters of little importance, such as color, odor, etc., but in the 

 country the plants are not named, and in a botanical garden they are 

 often badly named. . . . The geographic origin of the plants is there 

 almost always uncertain or unknown; the individuals are often modi- 

 fied by cultivation and crossing; fruits are rarely seen with the 

 flowers; rarely several individuals of the same species or several 

 related species; and still more rarely are botanists permitted to gather 

 enough specimens of an exotic plant to examine it to their satisfaction 

 and to preserve the proofs of their work." And he goes so far as 

 to head the chapter devoted to this consideration with the lines: 'Of 

 herbaria in general and of their superiority to every other zoological 

 or botanical collection.' It might have been added, truthfully, that 

 in a garden the representation of any given species is likely to be 

 transient, since the casualties to which living specimens are liable 

 are innumerable ; on the other hand, the specimens in the herbarium, 

 though subject to their own particular dangers, are far less likely to 

 suffer, and rarely disappear even in the course of very long periods of 

 time except as a result of gross carelessness. 



The principal collections of this class at the Missouri Botanical 

 Garden are, in the first place, the herbarium of Engelmann, which, 



* De Candolle, La Pliytographie, p. 365. 



