92 RESEARCHES ON FUNGI 



Their polygonal pores are shown in Fig. 6, p. 32. By making 

 suitable sections and using the microscope, it was found that ripe 

 spores were being discharged when the tubes on a young fruit- 

 body were only 1 mm. long. These observations lead me to suppose 

 that, in the case of the fruit-body for which it was found that the 

 spore-fall period lasted sixteen days, spore-emission had already 

 been in process for about a week before the spore-clouds were dis- 

 covered. Probably, therefore, in that instance the total spore-fall 

 period extended over about three weeks. 



By placing black paper beneath a ripe fruit-body for the purpose 

 of collecting the spores, it may easily be proved that each tube 

 emits spores continuously for several days. It may also be shown 

 that, except for a small zone about 1 mm. high at the mouth where 

 no spores are developed, every part of a tube produces spores. 

 A very large fruit-body, '2 ft. 2 in. across, was gathered from a 

 tree and a vertical section made through the pileus (Fig. 7, p. 33). 

 The section was placed on black paper. In twenty-four hours each 

 half-tube had produced a spore-deposit. The tubes were on the 

 average about 9 mm. long, and the spore-deposits, which were of 

 an even character, 8 mm. long, spores not having been produced 

 by a zone round the tube mouths. A photographic reproduction 

 of the deposits is shown in Plate IV., Fig. 28 ; and Plate IV., Fig. 27, 

 gives a spore-deposit collected from the mouths of hymenial tubes 

 disposed on a square inch of the pileus. We may draw the con- 

 clusion from these macroscopic observations that each hymenial 

 tube during its development liberates spores for several days from 

 every part of its spore-producing surface. 



The chief reason why one can see the clouds of spores so easily 

 in Polyporus squamosus is that the spores come off from the fruit- 

 bodies in such vast numbers. In one case, as already stated, a 

 single square centimetre of a fruit-body produced at the very least 

 44,450,000 spores in two or three days. A spore-cloud resembles 

 a steam cloud : the whole becomes visible owing to the vast number 

 of the microscopic constituent particles. The spores, too, are com- 

 paratively large (14'6x5*13 /A) and also colourless. They absorb 

 very little of the light falling upon them, but reflect and refract 

 most of it, so that they glisten. Like all other particles, the spores 



