GENERAL SUMMARY 263 



produce a spore print consisting of radiating lines corresponding to the 

 interlamellar spaces. Extremely minute convection currents give a hori- 

 zontal drift to the falling spores and cause the spore-deposit to become 

 cloudy. 



The number of spores liberated by large fruit-bodies amounts to thou- 

 sands of millions. A specimen of Psalliota campestris with a diameter of 

 8 cm. was found to produce 1,800,000,000 spores, one of Copnnus comatus 

 5,000,000,000, and one of Po!>/]>ont* .^uamosus 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 (40 x 28 x 20 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 4000 Mushrooms, each having 

 a diameter of 8 cm. 



Chapter VI. — 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 squamosus. It was found that 

 each hymenial tube was liberating spores from every part of its hymenium. 

 The visible discharge of spores appeared to be unaffected by light conditions 

 or by changes in the hygroscopic state of the atmosphere. The formation 

 of irregular clouds, wreaths, and curls of spores is not due to intermittent 

 spore-emission, but is brought about by air-currents sweeping beneath the 

 fruit-body. 



Chapter VII. — Spores falling from any fruit-body suspended in a suit- 

 able glass chamber, e.g. a closed beaker, can be seen in clouds or individually 

 without magnification by using a concentrated beam of light. Much vise 

 was made of this discovery in the research. 



The beam-of-light method can be used to make a A-ery simple and 

 effective laboratory demonstration of the discharge of spores from Mush- 

 rooms, Ac. It may be carried out with great convenience at any time by 

 using as material the mature xerophytic fruit-bodies of Lenzites 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. 



Chapter VIII. — Spore-discharge from any fruit-body under normal 

 conditions is continuous. The period of spore-discharge in some species 

 lasts for a few hours, in others days, and in yet others for weeks. With 

 the beam-of-light method a fruit-body of Schizophyllum commune and also 

 one of Polystictus versicolor were both observed to shed a continuous stream 

 of spores for sixteen days. A specimen of Letizites betulina shed spores for 



