OF THE FUNGI. 123 



Fresh leaves and stems infested by microscopic forms of 

 Fungi may be dried in the same way as the fronds of ferns 

 or leaves of the Phanerogamia, of which more will be said 

 hereafter. The only precaution necessary is, that the pres- 

 sure be not too heavy, and that the blotting paper be con- 

 stantly changed. As these Fungi arise, in the first instance, 

 from below the cuticle in which they excavate (so to speak) 

 little hollows, and then spread themselves around in yellow 

 or black pulverulent masses, too severe a pressure may 

 force them back into the cavities, or at least squeeze them 

 against the plane surface of the leaf, and thereby destroy 

 their natural habit and appearance. The reason why it is 

 advisable to make frequent changes of the drying material 

 is, that various forms of mould are developed wherever 

 there is moisture present. This is of little consequence 

 where large plants are being prepared, but may give rise to 

 serious errors when the objects are of a microscopic nature. 



The most difficult kinds to manage are the fleshy pileate 

 Fungi, those, I mean, included under the order Agaricacea?, 

 or Hymenomycetes, of systematic authors. Numerous ex- 

 periments have been made from time to time with a view 

 to strike out some plan of retaining their natural form and 

 features after death. But one arrangement after another has 

 had to be abandoned, and mycologists have been compelled to 

 fall back upon the earliest and withal the simplest method, 

 that of drying them. Even this simple method, however, 

 is not possible with the larger individuals, not only on ac- 

 count of their size, but because the substance of which they 

 are composed is so sensitive to the influence of moisture, that 

 it is hopeless to think of preserving them by any ordinary 

 treatment. Under the most favourable circumstances they 

 are shrivelled and shrunk out of all shape when taken from 

 the press. So the student must be content with having por- 

 tions only of the original plant at his command ; but these 

 may be prepared in such a way as to be full of instruction, 

 if he will follow out the suggestions I am about to offer. 



[But first of the parts which go to form an ordinary 



