io RESEARCHES ON FUNGI 



microscope, the spores are seen to be in groups of fours, each group 

 corresponding to a subjacent basidium. The drop of water, which 



A B C D 



H 



M N 



v i 



FIG. 3. Psalliota campestris. Diagrammatic representa- 

 tion showing the successive discharge of the four spores 

 from a basidium, as seen from above. A-D, stages in 

 the discharge of the first spore ; E-H, of the second ; 

 I-L, of the third ; and M-P, of the fourth. A, a drop 

 of water has just begun to be excreted where the right- 

 hand top spore joins its sterigma. B, about two seconds 

 later : the drop has grown. C, about three seconds 

 after B : the drop has attained its maximum size. D, 

 a fraction of a second after C : the spore has disappeared 

 carrying the drop with it ; the old position of the spore 

 is represented by a dotted circle. Similar explanations 

 apply to the other three horizontal lines of sketches, 

 each of which represents the discharge of a single spore. 

 The pause between the stages D and E, H and I, and 

 L and M, was in each case a few minutes. All the 

 stages from A to P were passed through in about 10 

 minutes. Magnification, 1,320. 



is excreted a few seconds before a spore is to be discharged, always 

 arises at the hilum of the spore, i.e. at the junction of the spore 

 with its sterigma. Now the hilum always faces toward the 

 longitudinal axis of the basidium-body. Hence the water-drop 



