136 EESE ARCHES ON FUNGI 



other species of Polyporus, and also upon species of Polystictus, 

 Dfedalea, and Boletus. The hymcnial tubes of many members of the 

 Polyporese are extremely narrow. Thus with the aid of the drawing 

 apparatus and a stage micrometer, it was found that the diameters 

 of the tubes at the mouths were on the average : for Polyporus 

 hirsutus, 0*3-0*4 mm. ; for Fomes vegetus, 0'15-0*2 mm. ; for 

 Fomes igniariiis, O'lo mm. ; and for Polystictus versicolor, 0*2- 

 0*25 mm. In Polyporus hirsutus and Polystictus versicolor, for 

 which species alone fresh material was available, the spores seemed 

 to be bombarded from the hymenium just as in the case of Polyporus 

 squaTnosus. They appeared to be projected outwards from the 

 hymenium and were seen to descend near the centres of the tubes, 

 at the mouths of Avhich they collected in heaps. Polyporus hirsutus 

 had tubes in the centre part of its fruit-body 2 cm. long. However, 

 by making transverse sections at different heights it was observed 

 that the spores were discharged throughout the whole length of a 

 tube. For Polystictus versicolor the tubes were often only 0'2 mm. 

 wide. Yet even in these the spores seemed to be shot outwards 

 from the hymenium. They appeared to travel a distance of about 

 Ol mm. toward the middle of the tubes before the horizontal velocity 

 had been reduced to zero. 



The species of Boletus investigated and the diameters of their 

 pores, as given by Massee/ were as follows : Boletus cltrysenteron, 

 1-1-5 mm.; B. felleus, up to 1 mm.; B.fiavus,^-! mm.; B. subto- 

 nientosus, f-1 mm. ; B. scaber, O'5-l mm. ; B. badius, 0"5-l mm. 

 Here, again, sections 1-2 mm. high were taken transversely through 

 the hy menial tubes, and looked into from above with the low power 

 of the microscope. In each, again, the spores were apparently shot 

 off from the hymenium into the tubes. In the wider tubes the spores 

 were seen to collect at the mouths in a zone around the walls, and in 

 the narrower ones they gradually formed a central heap. The im- 

 pression gained was that the spores Avere projected horizontally on 

 the average O'2-O-l mm., or about the same distance as for Polyporus 

 squamosus. Dxdalea unicolor (a very common fungus at Winnipeg) 

 behaved like the Boleti. 



In order to observe the fall of spores in members of the Agari- 

 ^ G. Massee, British Fumj us- Flora, 1892, vol. i. 



