252 



RESEARCHES ON FUNGI 



in the laboratory. The asci were found to be heliotropic, 1 and they 

 were caused to point directly upwards by enclosing the culture in a 

 dark-chamber and reflecting light downwards upon it through a 

 small top window. The spores, attached together in groups of eight, 



FIG. 81. Ascobolus immcrsun. a, five fruit-bodies, shown natural size, on 

 a section of horse dung. 6, fruit-body with five asci projecting from 

 the hymenium just before bursting. Two asci belonging to the next 

 younger series are to be seen almost hidden among the paraphyses in 

 the foreground, c, a young ascus and paraphyses. d and e, two fully 

 swollen asci isolated from the hymenium. /and g, burst asci which 

 have contracted to half their original length. In / the lid of the 

 ascus has opened as if attached by a hinge, y shows the result of an 

 ascus explosion watched under water with the microscope. The lid i 

 has been shot away along with the ascospore mass h. The eight 

 ascospores are attached by their gelatinous envelopes, b-i magnifi- 

 cation, 70. 



were then discharged in a vertical direction, so that they struck and 

 adhered to the underside of a horizontal glass plate placed 25 cm. 

 above the fruit-bodies. Further experiment showed that the maxi- 

 mum height of projection was about 35 cm. The culture was then 

 set in a large glass case which was exposed to the light at a labora- 

 1 For the significance of heliotropism in asci, ride Chap. IV., pp. 74, 75. 



