SPORE-DISCHARGE FROM AGARICINEAE 97 



and deep black, and it entirely lacks cystidia on the surface of 

 its gills. 



I procured the fruit-bodies of Coprinus curtus at will in winter- 

 time by proceeding as follows. Frozen dung-balls were collected 

 from the streets of Winnipeg and placed in a large glass vessel 

 which was then covered with a glass plate and set on a table 

 near a window in the laboratory. The dung-balls soon thawed. 

 Usually, after from 10 to 14 days, a number of fruit-bodies of 

 Coprinus curtus made their appearance on some, and often all, 

 of the dung-balls ; and, thereafter, for more than a week, a crop 

 of fruit-bodies of this same species came to maturity daily. The 

 dung-balls were sprayed or otherwise wetted as seemed necessary 

 to keep the culture in good condition. 



Several of the smaller Coprini show a distinct diurnal rhythm 

 in the production of their fruit-bodies. Thus a form of Coprinus 

 ephemerus, which commonly occurs on horse dung along with 

 C. curtus at Winnipeg, only opens its pilei about midnight, and 

 before 9 o'clock in the morning all its spores have long been 

 shed. There are several other small species of Coprinus which 

 behave like (7. ephemerus and, if one desires to study the expansion 

 of their pilei and the autodigestion of their gills, one must work 

 through the night instead of through the day. Coprinus curtus, 

 however, differs from these species in that it expands its diurnal 

 crop of fruit-bodies not in the night but in the morning and early 

 afternoon. It is on this account that I have chosen C. curtus as 

 a fungus upon which I might make various observations, including 

 those shortly to be recorded. 1 



The largest of the fruit-bodies which came up spontaneously 

 on the horse dung used in my observations had a stipe which, when 

 fully elongated, was 8 cm. high and a pileus which, when expanded 

 and flattened, was 1-75 cm. wide. The smallest were veritable 

 dwarfs. One of them, which was carefully measured, had a stipe 

 only 6 mm. high and a pileus only 1 5 mm. in diameter. The other 



1 The rhythmic production of fruit-bodies by certain small Coprini, like the 

 rhythmic production of asci hi Ascobolus and of sporangia in Pilobolus, is 

 undoubtedly due to the alternation of periods of light and darkness in every 24 

 hours ; but exactly how and when the light influences these fruiting structures 

 is at present unknown. 



