252 RESEARCHES ON FUNGI 



The horizontal component of each of these sporabolas is repre- 

 sented as being 0*2 mm. in length,^ while the form given to the 

 sporabolas is based on a mathematical calculation contained in 

 Volume I.^ 



An examination of Figs. 104 and 105 (pp. 242 and 249) reveals 

 that the zone of spore-discharge is situated at so small a height 

 above the free margin of the gill that a spore, when shot from its 

 sterigma into an interlamellar space, has only to fall a distance 

 of about • 3 mm. at most to escape from the pileus into the outer 



I I I 



« O-Oynm O-fTnm O-imJn 



Fig. 107. — Coprinus sterquilinus. A vertical section through a 

 gill showing a portion of the hymenium in the zone of spore- 

 discharge {cf. Fig. 105, p. 249) and the nature of the trajec- 

 tories of the spores {sporabolas) in still air. The spores are 

 shot out horizontally to a distance of about 02 mm. ; they 

 •then make a sharp curve and fall vertically downwards in 

 the interlamellar space. I, a long hasidium discharging 

 its spores ; d, a long basidium which has discharged its spores ; 

 s, a short basidium about to discharge its spores ; p, para- 

 physes. The magnification is shown by the scale. 



air beneath, where it may be carried off by the wind. This distance 

 is not much greater than that of the horizontal component of the 

 sporabola, which, as we have learned, has a length of about • 2 mm. 

 A consideration of these measurements, aided by an inspection 

 of Fig. 101 (p. 237) or Fig. 107 combined with Fig. 105 (p. 249) 

 justifies us in drawing the conclusion that the spores of Coprinus 

 sterquilinus can escape from a pileus even when the gills are inclined 

 to the vertical at angles of considerable size. 



If the spores in the zone of spore-discharge were to be shot 

 horizontally outwards from the hymenium for a uniform distance 

 of 0-2 mm., or even only 0-15 mm., the gills could be tilted from 



^ Vide supra. ^ These Researches, vol. i, 1909, pp. 184-191. 



