COPRINUS STERQUILINUS 251 



interlamellar spaces. The spores are shot away from their sterigmata 

 in an almost horizontal direction. By making observations with a 

 horizontal microscope in the manner described in Volume 1/ it was 

 found that, after discharge in still air, a spore travels horizontally 

 for about • 2 mm. into the interlamellar space, then curves sharply 

 downwards, and then falls vertically. This trajectory resembles 

 that of the spores of other Hymenomycetes. In Psalliota ca7npestris, 

 Coprinus niveus, C. curtus, Polyporus squamosus, and many other 

 species with relatively small spores, the length of the horizontal 

 part of the trajectory is only about 0-1 mm., whereas in Cojmnus 

 sterquilinus and Amanitopsis vaginata in which the spores are ex- 

 ceptionally large it is about • 2 mm., i.e. twice as long. The peculiar 

 trajectory traced out by a hymenomycetous spore when shot away 

 from its sterigma I have called a sporabola.^ Six Coprinus sterqui- 

 linus sporabolas are shown in Fig. 101, A (p. 237). From a study 

 of this illustration, it will be seen that the spores are not shot suffi- 

 ciently far to reach even the middle of the interlamellar spaces, 

 although these are represented as being only • 8 mm. wide.^ There 

 is therefore no danger of a spore being shot from one gill across the 

 interlamellar space so as to strike and stick to the opposing gill. 

 It will be remembered that a natural-size photograph ^of a spore- 

 deposit of Coprinus sterquilinus is reproduced in. Fig. 102 (p. 238). 

 Measurement of the width of the spore-lines of that spore-deposit 

 confirms the statement already made that the spores, before begin- 

 ning to fall vertically, are shot horizontally into the interlamellar 

 spaces to a distance of only about 0-2 mm. 



In Fig. 105 (p. 249) it was not possible to add trajectories of dis- 

 charged spores, owing to lack of space ; but several arrows are there 

 introduced which indicate the directions in which certain spores 

 would begin to travel when shot violently forward from their sterig- 

 mata. A piece of the right-hand hymenium of Fig. 105 is reproduced 

 in Fig. 107 with the addition of two complete sporabolas, one for 

 the spore of a long basidium and one for the spore of a short basidium. 



^ These Researches, vol. i, 1909, p. 142. 



2 Ibid., p. 185. 



3 This is about the minimum width for an interlamellar space. The inter- 

 lamellar spaces, as may be seen by reference to the spore-deposit shown in Fig. 102 

 (p. 238), vary in width from about 1 to 2-5 mm. 



