SPORE GERMINATION WITHOUT BACTERIA 85 



freshly-deposited horse dung, have practically no chance of ever 

 producing mycelia and of thus giving rise to fruit-bodies. Passage 

 of spores down the ahmentary canal of a horse, therefore, appears 

 to be an essential feature in the normal life-history of Coprinus 

 sterquilinus. 



It is probable that coprophilous Agaricineae in general, e.g. 

 PanaeoH, Strophariae, other Coprini, etc., resemble Coprinus 

 sterquilinus in that the spores which germinate and give rise to 

 fruiting myceha on dung in pastures, etc., are not those which are 

 blown on to the surface of the dung by the wind but are those 

 which have passed down the ahmentary canal of some herbivorous 

 animal. So dependent on herbivorous animals have C. sterquilinus 

 and other coprophilous Agaricineae become that their geographical 

 distribution is doubtless limited by the geographical distribution of 

 the animals with which they are associated. 



Presence of Bacteria Not Required for the Germination of the 

 Spores of Coprinus sterquilinus. — In 1915 Miss Baden 1 pubhshed 

 a paper in which she asserted that the spores of Coprinus sterquilinus 

 germinate (1) only in the presence of bacteria, and (2) only at a 

 temperature above 20° C. A series of experiments carried out by 

 S. G. Churchward and myseK in 1915 yielded results which show 

 that both of Miss Baden's conclusions are erroneous. 



Churchyard and I found that from 80 to 90 per cent, of the 

 spores of Coprinus sterquilinus germmate in hanging drops of the 

 following sterilised solutions : (1) horse-dung decoction, (2) malt 

 extract, (3) bean decoction (Phaseolus), (4) Pollock's optimum soil- 

 fungus medium, and (5) nutrient gelatine. 



(1) The dung decoction was made as follows. Fresh horse-dung 

 balls were placed in a bag made of cheese-cloth, which was squeezed 

 so that as much of the juice was expressed as possible. The juice 

 was then boiled, to get rid of the coagulable proteins, and filtered. 

 The filtrate was then placed in a flask with a cotton-wool plug and 

 sterihsed by heating in a steam sterihser at a temperature of 100° C, 

 for one hour. 



(2) To prepare the malt extract, 20 grams of malt were crushed 



1 M. L. Baden, " Observations on the Germination of the Spores of Coprinus 

 sterquilinus Fr.," Annals oj Botany, vol. xxix, 1915, p. 141. 



