COPRINUS PLICATILIS 139 



with the pavement-Hke paraphyses, have the normal coprinoid 

 arrangement. The zones of spore-discharge are unusually wide but 

 they nevertheless proceed from below upwards on each gill. The 

 loss of autodigestion is doubtless associated with the fact that the 

 pileus, on opening, becomes spread out like a parasol. The gills split 

 along their median planes from above downwards and thus become 

 Y-shaped in vertical transverse section. The upper parts of the 

 gills thus come to look downwards and the spores there discharged 

 can escape freely from the pileus without any danger of striking an 

 obstacle. It is noticeable, however, that one side of the unsplit 

 lower portion of a gill is often powdered black with spores which 

 have failed to gain their freedom. This appears to be due to the 

 fact that the side so powdered has looked slightly upwards and has 

 therefore caught the spores on its surface after they have been shot 

 away from the hymenium and have fallen vertically for a certain 

 distance. The loss of autodigestion is therefore associated with a 

 certain loss of efficiency in spore-discharge. 



In certain other small Coprini, e.g. Coprinus curtus (Vol. II, 

 Fig. 32, p. 96), the pileus also opens out parasol-wise before spore- 

 discharge begins and each gill becomes Y-shaped in cross-section. 

 However, in all these species the lower part of the vertical portion 

 of each gill distinctly undergoes autodigestion which can be observed 

 either with the eye or with the microscope, so' that here the most 

 characteristic feature of the mechanism of Coprinus fruit-bodies 

 has not been eliminated. My investigations upon numerous small 

 species of the genus Coprinus have convinced me that Coprinus 

 plicatilis alone has lost the power of reducing its gills by auto- 

 digestion during spore-discharge ; and I therefore cannot agree 

 with Massee when he states that many species included in the genus 

 Coprinus have dry and non-deliquescent gills. 



There is a fungus which has come up spontaneously on horse 

 dung several times in my laboratory at Winnipeg. It so much 

 resembles the Coprinus plicatilis which occurs in such abundance 

 in grassy fields in England, that at first 1 thought the two species 

 were identical ; but a careful comparison has convinced me that 

 they are distinct. The two fungi are similar in their brownish 

 colour when young, in their umbonate disc becoming depressed at 



