TRANSACTIONS OF SECTION K. 675 
TUESDAY, AUGUST 31. 
The following Papers and Reports were read :— 
1. The Production, Liberation, and Dispersion of the Spores of 
Hymenomycetes. By Professor A. H. Recinatp BuiEr, Ph.D. 
The number of spores liberated by large fruit-bodies amounts to 
thousands of millions. A specimen of Psalliota campestris with a diameter 
of 8 cm. was found to produce 1,800,000,000 spores, one of Coprinus comatus 
5,000,000,000, and one of Polyporus squamosus 11,000,000,000. The rate 
of elimination of the spores or young plants by death can be shown to be 
enormous. The most prolific kind of fish is not so prolific as a mushroom 
plant. It was estimated that a large fruit-body (40x28x20 cm.) of Lyco- 
perdon bovista, Linn, the giant puff-ball, contained 7,000,000,000,000 
spores, or as many as would be liberated by 4,000 mushrooms, each having 
a diameter of 8 cm. 
With the unaided eyes by daylight, clouds of spores were observed to 
be given off continuously for thirteen days from the underside of a large 
fruit-body of Polyporus sqyuamosus, It was found that each hymenial tube 
was liberating spores from every part of its hymenium. 
Spores falling from any fruit-body suspended in a suitable glass 
chamber, e.g. a closed beaker, can be seen in clouds or individually without 
magnification by using a concentrated beam of light. Much use was made 
of this discovery in the research. 
The beam-of-light method can be used to make a very simple and effective 
laboratory demonstration of the discharge of spores from mushrooms, &c. 
It may be carried out with great convenience at any time by using as 
material the mature xerophytic fruit-bodies of Lenzztes betulina, 
Schizophyllum commune, ‘Polystictus versicolor, &c. These can be kept dry 
in bottles for months or years. After wet cotton-wool has been placed 
above them they quickly revive, and they begin to shed their spores within 
six hours. The emission of the spores continues for days. 
The four spores on each basidium are discharged successively within a 
few seconds or minutes of one another. 
Each spore is shot out violently to a distance of about #4; mm, 
The rate of fall of spores in still air was determined for the first time. 
A-small piece of a fruit-body was placed in a vertically-disposed compressor 
cell. The falling spores were observed with a horizontal microscope, and 
their rate of fall accurately recorded upon a revolving drum. 
The first direct test of the applicability of Stokes’ Law to the fall of 
microscopic spheres in air has been carried out by determining the size, 
specific gravity, and terminal velocity of the spherical spores of 
Amanitopsis vaginata. The rate of fall of the spores was found to be 
about 46 per cent. greater than was expected. While, therefore, the 
observed speed has proved to be of the same order of magnitude as the 
calculated, Stokes’ Law has not been confirmed in detail. No fully satis- 
factory reason for the discrepancy between theory and observation has so: 
far been found. 
The rate of fall of hymenomycetous spores ranges from 0°35 to 60 mm. 
per second. It varies with the size of the spores, their specific gravity, 
and the progress of desiccation. The relatively very small spores of 
Collybia dryophila in very dry air were found to fall at an average rate 
of 0°37 mm. per second, whilst the relatively very large spores of Amani- 
topsis vaginata in a saturated chamber attained a speed of 6:08 mm. per 
second. The spores of the mushroom (Psalliota cam pestris), shortly after. 
they have left the pileus, fall at a speed of approximately 1 mm. per 
second. 
Kee 
