SCHIZOPHYLLUM COMMUNE 



117 



until at length they come to consist solely of two deep, apposed 

 plates. After a young gill has become connected with the 

 pileus margin, its two plates separate from one another slightly 

 at their peripheral ends. This separation of the gill plates, as 

 growth proceeds, becomes more and more marked, and at length 

 involves the pileus flesh. The peripheral end of every long and 

 deep gill thus comes to resemble in cross section the deepest 

 gills shown in Fig. 41, E. The whole gill system may be regarded 

 as being made up of branched fasciculi. 



Schizophyllum commune, as we have already seen, is a xero- 

 phyte. In moist weather the gills all look 

 vertically downwards, as in the Mushroom, 

 and spore-discharge takes place for days 

 from their hymenial surfaces (Fig. 41, E). 

 When dry weather comes, and the wooden 

 substratum gradually loses its water, de- 

 siccation of the fruit-body sets in. The 

 emission of spores soon ceases, and the 

 two halves of each gill begin to diverge 

 below (Fig. 44). As desiccation proceeds, 

 the gill plates become curled outwards 

 at their edges. When a fruit-body has 

 become quite dry, one finds that the 

 longest gills which have separated into 

 two halves to their bases, have covered in 

 the shorter ones. Each fasciculus of gills in cross section now 

 presents a very curious appearance (Fig. 41, F). It is evident 

 that the relative sizes and amounts of splitting of the different 

 gills are admirably adapted to facilitate the closing up of the 

 fasciculi. In a state of desiccation a fruit-body has its hymenium 

 completely hidden from external view, and the pileus is temporarily 

 provided below with a hairy covering. 



Whilst in the dried condition a fruit-body can retain its 

 vitality for at least two years, and, with intermittent revivals, 

 for at least three years. When rain comes again, the woolly 

 upper surface of the pileus sucks water in by capillary attraction, 

 and the gill halves at once begin to unroll and reappose themselves 



Fig. 44.— Section through a 

 fasciculus of gills of Schizo- 

 phyllum commune showing an 

 early stage in the divergence 

 of the gill plates. About 

 8 times the natural size. 



