PANUS STYPTICUS LUMINESCENS 



391 



a dense spore-deposit. 

 Some of the spores were 

 then sown on dung- 

 agar poured into Petri 

 dishes. After a few 

 days they germinated. 

 The mycelia grew slow- 

 ly as if in an unsuit- 

 able medium. When 

 they had attained a 

 diameter of 1-2 mm., 

 I examined them night 

 after night in the dark- 

 room, but could not 

 detect any light coming 

 from them. In the 

 belief that this miglit 

 be due to the small 

 amount of mycelium 

 present or its lack of 

 vigour, I therefore 

 made some cultures 

 upon wood. Some 

 blocks of Silver Birch 

 wood, 3 inches long, 2 

 inches wide, and octa- 

 gonal in cross-section, 

 were boiled in water, 

 then taken out of the 

 boiling water and 

 plunged in cold water, 

 this process being re- 

 peated several times 

 until the blocks were 

 waterlogged. Then the 

 blocks were placed in 

 large glass jars provided with cotton-wool plugs (Fig. 170) and were 



Fig. 170. — Cultitie of tlie luiuiiiou.s uiVfeliuiii of 

 Panus stypticus physiological form luniinescens. 

 Spores obtained from fruit-bodies gathered at 

 Saint Paul, Minn., U.S.A., were sown on the top 

 of the sterilised block of Birch wood which rests 

 on wet cotton wool. The mycelium is now 

 spreading over the block. Photographed by 

 daylight. Abovit i tlie actual size. 



