1915] 



OVERIIOLTS STUDIES IN THE POLYPORACEAE 677 



basket or other receptacle in which a fairly high humidity 

 will be maintained, so that the liberation of the spores will 

 not be prematurely stopped by the drying-out of the tissues of 

 the fungus. If the specimens are dry when brought into the 

 laboratory they may be moistened thoroughly with water and 

 then treated as described above. One unaccustomed to this 

 procedure will be surprised to find how large a percentage 

 of the collections so treated will produce a good spore print. 

 Specimens collected on the warm days that frequently come 

 in January and February have often been treated in the above 

 manner with gratifying and surprising results. When desic- 

 cation takes place by exposure to the air the vitality of many 

 species is not destroyed. Buller 1 was able to restore normal 

 vitality to such plants by placing wet cotton-wool on their 

 upper surfaces. He was even able to revive the fruit bodies 

 of Daedalea unicolor after they had been exposed to ordi- 

 nary air at room temperatures for eight years and three 

 months, and of Schizophyllum commune after an exposure of 

 six years and three months. In most species, e. g., Polyporus 

 versicolor, P. hirsutus, and Lenzites betulina the vitality was 

 retained for a period of but two to three years. 



Sectional preparations. — In case one is working with ma- 

 terial that has been in the herbarium for several years the 

 above method will not answer. Neither does it furnish any 

 evidence as to the other microscopic characters of the plants. 

 One must then resort to sectional preparations. These are 

 cut free-hand with a very sharp sectioning razor. Free-hand 

 sections are quickly made and the results from them are 

 usually better than from microtome sections. It is impossible 

 for the spores to retain their position on the basidia when 

 subjected to the different processes involved in preparing ma- 

 terial for microtome sectioning. The first requisite in suc- 

 cessful free-hand sectioning is material in good condition ; the 

 second is a very sharp razor (preferably flooded with alcohol) ; 

 the third is some little skill and experience. The hymenium of 

 the specimen is first moistened with alcohol, then with water, 



1 Researches on fungi, pp. 105-111. 1909; and in Trans. Brit. Myc. Soc. 4: 

 106-112. 1913. 



