COPRINUS STERQUILINUS 183 



them for fifteen seconds ; and the temperature of the laboratory 

 was maintained at about 20° C.^ 



The most rapid and least troublesome way of obtaining a fresh 

 crop of fruit-bodies is by inoculating the sterilised dung-balls with 

 pieces of dung bearing a vigorously growing mycelium. Cultures 

 made in this way and kept at a temperature of about 20° C. usually 

 produced mature fruit-bodies within thirty days and, under the 

 most favourable conditions, at the end of twenty days. By using 

 the mycelial method of inoculation in place of the spore method, 

 the saving of time in the production of new fruit-bodies was at 

 least a week. 



Description of the Maturing Fruit-body. — The young fruit - 

 body begins its development as a rudiment upon the mycelium 

 clothing the exterior of a dung-ball. At first it is merely a globular 

 weft of hyphae ; but, as it increases in size, it becomes compact 

 within and assumes a conical form. The upper part of the cone 

 becomes yellowish and marked off from the lower part by a slight 

 constriction. The lower part is the solid stipe-base, the function of 

 which will be discussed in Volume IV : in most of my crystallising- 

 dish cultures it soon assumed a more or less globular form (Fig. 69, 

 p. 180). The upper part of the cone is the rudimentary pileus 

 enclosing the rudiment of the stipe-shaft. The pileus, after being 

 brought into the light by the growth of the stipe-base, is barrel- 

 shaped (Figs. 69 and 70). About a week after the pileus has begun 

 its development in the light, the stipe-shaft elongates, the pileus 

 expands, and the spores are liberated into the air. 



The upper part of the pileus in its youngest state has a smooth 

 greasy-yellow appearance but, as the pileus increases in size, this 

 appearance becomes confined to the disc where it persists until 

 the fruit-body collapses. The sides of the young pileus become 

 broken upon the exterior into small scales and, before the stipe 

 begins to elongate rapidly and shortly afterwards, they are snowy 



1 Since this was written Miss Irene TVTouncc, working in my laboratory with 

 large test-tube cultures, has observed that the life-history of Coprinus sterqiiilinvs, 

 from spore to spore, is usually completed in 24-31 days. Vide I. Mounoe, " Homo- 

 thallism and the Production of Fruit-bodies by Monosporous Mycelia in the Genus 

 Coprinus," Trans. Brit. Myc. Soc., vol. vii, 1921, p. 203. 



