COPRINUS ATRAMENTARIUS 263 



made since 1910, has brought to light the following facts which 

 I had previously overlooked : (1) the dimorphism of the basidia, 

 (2) the accumulation of waste spores on the gill-edges, and (3) the 

 excretion of a water-drop from the hilum of each spore just before 

 spore-discharge. In the account of C. atramentarius about to be 

 given in this Chapter there will be incorporated all my observations, 

 both old and new, and, in addition, a new and imjjroved series of 

 illustrations. 



Distribution and Habitat. — Coprinus atramentarius is one of 

 the largest and commonest species of its genus. It is widely dis- 

 tributed over the earth's surface, and has been found in Europe, 

 North America, Australia, and Kerguelen Island.^ I, myself, have 

 often seen it in England and Western Canada. The genus Coprinus, 

 according to Hennings,^ contains about 175 species. Whilst most 

 of them grow upon dung or dunged ground, a few come up on dead 

 stems or wood. Coprinus atramentarius belongs to the minority. 

 It is never coprophilous but, so far as my observation has gone, is 

 most frequently found at the sides of partly buried stumps and 

 logs of wood. In England, I have often noticed the fruit-bodies 

 at the foot of gate-posts and the supports of fence rails. At Gimli 

 on Lake Winnipeg, a forest of poplars {Populus tremvloides and 

 P. balsamifera) was cut down to open up a tract of land for cattle, 

 and the stumps of the trees were left protruding from one to two 

 feet above the surface of the ground. A few years afterwards I 

 visited the spot and found that the fruit-bodies of Coprinus atra- 

 mentarius were coming up about the stumps in great abundance. 

 There were literally hundreds of fruit-body clusters. Upon in- 

 vestigation I found that a number of these clusters were seated 

 directly on root-spurs. It therefore seems probable that the 

 mycelium of Coprinus atramentarius is specialised for the destruc- 

 tion of wood. However, the manner in which the fungus passes 

 through its vegetative existence under natural conditions still 

 awaits an exact investigation. At attempt made by myself to 



^ G. Massee, " A Revision of the genus Coprinus," Ann. of Bot., vol. x, 1896, 

 p. 143. 



2 P. Hennings, in Engler u. Prantl, Die nat. PJlanzenfamilien, Tail I, Abteil. 

 I**, p. 205. 



