222 RESEARCHES ON FUNGI 



sterquilinus does not become swollen in chlor-zinc iodine, so that 

 I have found it impossible to use that reagent for determining 

 whether or not a colourless exospore completely envelopes an 

 endospore. 



As in all other Coprini and in chromosporous species of 

 Agaricineae generally, in Coprinus sterquilinus there is an apical 

 l^ore at the summit of the spore. At the mouth of this pore the 

 wall is thinner than elsewhere and colourless ; and, not improbably, 

 it consists solely of exospore. The pore serves for the emission of 

 a single germ-tube. Since there is but one pore, only one germ- 

 tube is emitted. Where in the Hymenomycetes, e.g. Polyporus 

 squamosus, the spore- wall is very thin, no pores are present, for 

 none are required, and several germ-tubes may arise in diverse 

 and variable positions at the spore's outer surface.^ The spore 

 of the chromosporous species of Agaricineae, which possesses thick 

 and pigmented walls and one apical pore, and which emits a single 

 germ-tube through the pore, is evidently much more specialised 

 than the thin-walled colourless spore of most Leucosporae, which 

 lacks a pore and emits germ-tubes varying both in number and 

 place of origin. There seems every reason to believe that, in the 

 course of evolution, the former has arisen from the latter and not 

 vice versa as Massee once would have us believe. ^ 



A few somewhat curious observations on the behaviour of un- 

 ripe spores under certain artificial conditions may here be described. 

 Some full-sized but colourless spores were removed from their 

 sterigmata by rubbing a gill in a drop of water upon a glass slide. 

 Some of these spores were then put in a hanging drop of water 

 and others in a hanging drop of juice squeezed out from the gill. 

 The spores in the water became strongly vacuolated and their 

 walls remained colourless ; but the spores in the juice from the 

 gills continued their ripening processes, for in the course of seven 

 hours their walls became dark brown. Subsequently some of these 

 spores germinated. 



1 A. H. R. Buller, " The Biology of Polyporus sqiiamosus Huds., a Timber- 

 destroying Fungus," Journal of Economic Biology, vol. i, 1906, Plates VI and VII. 



2 G. Massee, "A Revision of the Genus Coprinus," Ann. of Bot., vol. x, 1890, 

 pp. 129-130. 



