130 



RESEARCHES ON FUNGI 



but also closely crowded (Fig. 48). In one fruit-body which I 

 investigated, there were 2,080 tubes in 1 square cm. of a tube-layer. 

 Since each tube is lined with a hymenial layer from top to bottom, 

 other things being equal it follows that the longer and narrower 

 the tubes, and the more the tubes are crowded together, the more 

 spores can be produced by the tubes above any given area of 



the pored surface. As 

 recorded in Volume I, 

 the inner surface of 

 the tubes of a single 

 layer of tubes in one 

 fruit-body was found 

 to be 148 times as 

 great as the flat under 

 surface of the flesh to 

 which the tubes were 

 attached, so that the 

 specific increase of the 

 hymenial surface of the 

 fruit-body due to the 

 presence of a single 

 layer of tubes was 148. 

 Taking three years 

 together the specific 

 increase was 49 3. * 

 Owing to the high 

 specific increase of 

 hymenial surface it 

 can be no matter for surprise that, as White has directly observed, 

 Forties applanatus produces an almost incredible number of spores. 

 White, using the methods I employed for Polyporus squamosus, 

 found that a fruit-body of Forties appUnatus having a pored area of 

 about 1 square foot liberated 30,000,000,000 spores in 24 hours. 2 



One square* foot equals 930 sq. cm. Reckoning 2,080 tubes 

 to 1 sq. cm., the number of tubes on the under side of White's 



1 Vol. i, pp. 32-33. Fomes vegetus is merely a synonym for F. applanatus. 



2 J. H. White, loc. cit., p. 140. 



FIG. 47. Fomes officinalis. A fruit-body with 15 

 annual layers of hymenial tubes, and therefore 

 15 years old ; length 1 foot, breadth and depth 

 each 7'5 inches, weight 5 Ibs. Collected at 

 Algonkin Park, Canada. Photographed by 

 J. H. Faull. About | natural size. 



