I 82 



RESEARCHES ON FUNGI 



continue in a more or less marked manner for about 10 cm. 



A final, terminal, and fairly uniform velocity was then reached, 

 the time required for its attainment being less 

 than half a minute after the spores had been 

 liberated from the gills. The following curves 

 (Fig. 63) give the results of the observations. 

 Each velocity plotted is the average of about 

 twenty-five velocities recorded in sequence. 



The curve for the Mushroom spores is re- 

 markable in that it first of all sinks and then 

 rises again. Possibly this is accounted for on 

 the supposition that the spores buckle up 

 after a certain stage of desiccation has been 

 reached. Such a mode of contraction would 

 decrease the surface exposed in falling, and 

 thus increase the velocity. As a matter of 

 fact, Mushroom spores, when drying on a glass 

 slide, rapidly become indented on one side so 

 that they more or less assume the form of a 

 boat. 



A general conclusion which may be arrived 

 at from the data contained in this chapter 

 is, that in nature spores fall most rapidly 



FIG. 02. Plan and , L . ,. , * ... . . , 



section of a long almost immediately alter liberation from the 

 me a aTurTng Sed t f he sterigmata whilst they are passing out from 

 rates of fall of the fruit-bodies between gills, down tubes, &c., 



spores at different . 



distances from the and that after they have drifted in the COn- 

 gills. b, brass : r u r i_ 



g, glass , p, piece vection currents or the outer air tor about 

 of pileus. At s h a if a minute, they reach a steady terminal 



and t are shown 



two fields as seen velocity considerably less than the initial. 



with the horizon- 



tai microscope 6 We can only suppose that at the moment or 

 below 111 the "gills liberation the spores are fully turgid, and that 

 respectively. One- by the rapid loss of water they become dried 



half actual size. J J 



up in less than a minute. It is certainly a 

 good arrangement that the spores should fall down between the 

 gills or in hymenial tubes, &c., with the greatest velocity, for 

 they thus escape from the fruit-bodies with the least risk of 



