1903 The Study of Microfungi 49 



First find your microfungus; and allow me to say that 

 these small plants need patient and careful search among 

 the fields and waysides. They rarely obtrude themselves 

 upon one's notice like a flower, but hide away among 

 tangled vegetation, for the most part on the under-surfaces 

 of leaves, and on those nearer the ground rather than those 

 more recently unfolded. 



A word of caution may be given here not to mistake for a 

 fungus every discoloured spot or streak that one finds upon 

 leaves. Insects are responsible for many of these spots — 

 (1) by causing minute galls or pseudo-galls, (2) by punctur- 

 ing the leaves, thus producing a change of colour, (3) or else 

 a collection of hair-like irritation-cells, the real nature of 

 which is only apparent under the microscope. 



Having found a plant affected with a fungus, pick two 

 leaves to dry and one to examine fresh and from which 

 to make sections. A discarded directory will do to dry 

 the leaves in ; then fasten them on cards, some 4 by 5 inches, 

 so as to exhibit each side of a leaf. It is well to fasten a 

 piece of tissue-paper over the top of the card so as to pro- 

 tect the spores from being rubbed off. The back of the 

 card should bear the name of the fungus and its stage of 

 growth, and that of the host-plant upon which it grew : also 

 insert the place where it was found, and the date. 



Only a very small piece of leaf is needed to cut a section 

 from, through one or more of the spots or sori of the fungus. 

 To do this, peel a young shoot of elder of all the bark, and 

 then split a 3- or 4-inch piece of this down the middle, then 

 place the piece of leaf between the halves of pith, and shave 

 off pith and all as thinly as possible with a sharp razor. 

 It is necessary to sharpen the razor frequently, as sections 

 cannot be made thinly enough unless the edge be keen. 

 Now remove the pieces of pith with a needle mounted in a 

 wooden handle, and transfer the section to a glass slide with 

 a wet camel's-hair brush, and mount in Farrant's solution 

 or in glycerine-and-water ; and lastly, seal the cover-glass 

 with any of the ordinary cements. 



A common, if not the regular, way of preserving the leaves 

 is to fold them loosely in scraps of paper, so that they can be 

 readily removed for examination ; but I think this a trouble- 



vol. 11. — no. 5. D 



