LUMINESCENCE 



131 



is not understood. In T. deformans discharge at night appears to 

 be an adaptation favoring infection. 



The perithecial beaks of Neurospora sitophila have been shown 

 [Backus (1937)] to be positively phototropic and to discharge 

 their spores toward the light. Observations indicate also that the 

 beaks of such rostrate fungi as Gnomonia, Ceratostomella, and 

 Diaporthe are positively phototropic. The phototropic responses 

 of such genera as Linospora and Ophiodothella, whose perithecia 



May 18 



May 19 



May 20 



May 21 



Fig. 20. Period of ascospore output from a stroma of Hypoxylon jus cum 

 at a temperature within the range 17 to 19.5° C. (After Ingold.) 



and asci lie horizontally and whose beaks stand vertically, should 

 constitute an interesting subject of study. 



LUMINESCENCE 



Nearly everyone has noted that old stumps, decaying logs, and 

 leaf mold may emit a weird glow at night. This phenomenon, 

 which has been called "fox fire," is usually caused by luminous 

 fungi, most of which are Hymenomycetes. Various other or- 

 ganisms, including species of bacteria, flagellates, sponges, jelly- 

 fish, hydroids, bryozoans, marine worms, earthworms, Crustacea, 

 myriapods, insects, molluscs, squids, and fish, are known to emit 

 light. An informative treatment of this general subject is given 

 in Harvey's (1940) Living Light. Buller (1924, 1934) studied 

 luminescence in Paints stipticns and Omphaiia flavida, and his 

 account of this phenomenon among fungi will be found very 

 stimulating;. 



According to Buller's list (1924), the pilei of the following 

 species are luminous: Clitocybe illndens, Panns incctndescens, P. 



