THE SPORABOLA 



189 



The structure of a Mushroom is such that the spores are shot out 

 into the spaces between the gills, where they fall down freely in 

 response to gravity. They thus escape from the fruit-body without 

 danger of touching, and thereby adhering to, the hyinenium. 



The hymenium on the side of a gill may be likened to a battery. 

 The basidia are the guns and the spores the projectiles. Each gun 

 is capable of shooting off four projectiles 

 in succession at intervals of a few seconds 

 or minutes. The battery is so splendidly 

 organised that the guns are brought for- 

 ward, mounted, and fired off in succes- 

 sion. Thus a heavy and continuous 

 boinbardment is maintained for days or 

 weeks, and only ceases when the am- 

 munition has become exhausted. The 

 object of the miniature gunnery is to 

 drop the spores into the spaces between 

 the gills, so that they may fall out from 

 the fruit-body without touching one 

 another or any part of the hymenium. 

 The success with which a large Mush- 

 room or Polyporus is able in the course 

 of a few days to liberate thousands of 

 millions of spores, and entrust them to 

 the scattering winds, may well excite our 

 admiration. 



In a few rare instances, owing to 

 imperfection in the structure of the pilei, the spores are not all 

 able to escape into the outer air. Thus, for example, in Nolanea 

 pascua the gills often become locally powdered with the red spores. 

 This is due to the fact that the gills are somewhat wavy, and there- 

 fore not properly disposed in vertical planes. The adhesive spores, 

 when falling, catch and stick on the projecting parts. 



FIG. 66. Vertical section 

 through two hymenial tubes 

 from the pileus of Polyporus 

 squamosus. The arrows show 

 the sporabolas described by 

 the spores when they are 

 discharged, h, the hyme- 

 nium. About 8 times natural 

 size. 



