82 RESEARCHES ON FUNGI 



designed to reduce convection currents to the least possible 

 minimum (Fig. 58, p. 167, and Fig. 62, p. 182), spore prints of the 

 gills can be obtained when the gills are 2-10 cm. above the 

 collecting surfaces. 



It seemed of interest to determine the number of spores liberated 

 from a few typical fruit-bodies. It has often been stated that 

 Mushrooms, &c, produce spores by the million. That this is no 

 exaggeration will be clear from an account of an investigation into 

 the number of spores produced by fruit-bodies of Psalliota cam- 

 pestris, Coprinus comatus, Polyporus squamosus, and D&dalia 

 confragosa. 



Psalliota campestris. — Fruit-bodies just about to liberate their 

 spores were obtained from a field. The stipe of one specimen was 

 cut off, and its pileus, which had a diameter of 8 cm., was placed 

 in contact with a sheet of white paper. A suitable covering was 

 used to keep off air-currents. In two days the discharge of spores 

 appeared to be completed. 



The paper containing the spores was placed in 100 cc. of distilled 

 water, and the whole stirred vigorously until the spores had been 

 washed off the paper and spread evenly through the fluid. A 

 Leitz-Wetzlar counting apparatus was then employed and the 

 number of spores which settled on the squares carefully counted. 

 As a result of a number of trials, it was calculated that the spore- 

 deposit represented approximately 1,800,000,000 spores. Since all 

 these spores fell within forty-eight hours, we must conclude that 

 on the average about 40,000,000 fell during each hour of the 

 spore-fall period. 



Coprinus comatus. — In calculating the number of spores in this 

 species, a more direct method was employed than that described 

 above. A gill of Coprinus comatus can easily be split down its 

 median plane. If, by taking advantage of this fact, one obtains 

 half a gill and then places it in a closed compressor cell so that 

 the hymenium looks upwards, one can easily observe the basidia 

 and spores with the microscope. They form a very regular and 

 striking pattern (Plate III., Fig. 15). With the aid of a drawing 

 apparatus, it was found that the number of basidia on 0*01 of a 

 square millimetre was 34, where the spores Avere ripening. As 



