370 RESEARCHES ON FUNGI 



to purple-brown, chocolate-brown, and finally to almost black. 

 As soon as the pileus has expanded, the surface of each gill is seen 

 to be mottled, owing to the fact that pigmented spores are present 

 on the darker areas and unpigmented spores on the lighter areas. 

 The mottling is somewhat fine in texture, but can easily be 

 detected with the naked eye, and it persists for several days until 

 the pileus is nearly exhausted. The edge of the gill is whitish and 

 minutely denticulate. 



The stipe is 5-10 cm. long, 1 -2-2 cm. thick, bulbous when young, 

 at maturity cylindrical but often tapering somewhat to the lower 

 end ; sometimes it is thicker below than above or even sub-bulbous 

 at the base. It is white. The flesh is solid except for the central 

 core which is more or less stuffed with looser fibrils. The stipe 

 is easily separated from the substance of the pileus. 



The velum is thin, white, silky, and very fragile. It is stretched 

 horizontally as the pileus expands and finally torn, so that an 

 annulus is formed about the middle of the stipe while fragments 

 cling to the pileus margin. The annulus is more or less sheathed 

 to the stipe, margin spreading or reflexed, torn, often deciduous, 

 shrivelling as the fruit-body ages and thus becoming more and more 

 inconspicuous. Sometimes it is in the form of a cortina. 



The spores are purple-brown, elliptical, 7-9 ^ long, breadth 

 and depth equal, each about 5-6 /JL. 



A fruit-body, when fresh, has a weak but pleasant odour and 

 an excellent flavour when cooked for food. As soon as the pileus 

 has ceased to shed spores, i.e. about the sixth day after expansion, 

 the stipe and pileus both collapse and become converted rapidly 

 into a very dark putrescent mass. 



A few comments on the descriptions given by other authors 

 will now be made. The colour of the gills is chiefly due to the 

 cell-sap in all the cells. This sap is at first colourless but, as the 

 pileus expands, it becomes pink. As the pileus flattens, the pink 

 colour of the cell-sap changes to brown ; and, as the pileus ages, 

 the brown colour of the cell-sap becomes progressively darker 

 until it is almost black. Atkinson x states that the gills "soon 

 become pink in colour and after the cap is expanded they quickly 

 1 G. F. Atkinson, loc. cit., p. 19. 



