6o British Fims'i, 



s 



the same species, are important characters that have 

 been almost entirely neglected. The same remarks 

 apply to the other groups of large fungi. 



In reply to this statement, it may be asked, Are 

 microscopic characters of more value than the more 

 superficial ones adopted by Fries ? The value of a 

 character depends entirely on its constancy, and 

 evidence is not wanting to prove that such organs as 

 asci, basidia, cystidia, paraphyses^ and more especially 

 spores and gonidia are more constant than other 

 portions of the hymenophore, perithecia, or gonidio- 

 phores respectively. A little practice will enable 

 any one to cut sections through the gills of an agaric 

 that will show all the organs in their natural position, 

 and when stained with a very weak solution of eosin 

 in water to which a drop or two of acetic acid is added, 

 the preparation may be permanently mounted in 

 glycerine jelly. In the Ascomycetes, where spore 

 characters are of great importance in the discrimina- 

 tion of species, it will be found of great advantage to 

 have miscroscopic preparations as standards of com- 

 parison when examining new material. There is a 

 tendency in some quarters at the present day to look 

 upon spores as the only feature of importance inform- 

 ing genera and species. As to whether an additional 

 septum in a spore is really of generic value depends 

 entirely on the view as to what the term genus really 

 means, a problem at present unsolved, and likely to 

 remain so until we know very much more of the life- 

 history of at least the leading forms belonging to 

 each of the large groups, and in the present unsettled 

 state of the subject it is important in noting the 



