BIOLUMINESCENCE IN XYLARIA 



417 



of Xylaria Hypoxylon, in which he asserted that, after having made 

 pure cultures of the fungus on various media, he was able to con- 

 firm Ludwig's state- 

 ment that the fungus 

 is luminous. " I 

 too " says Gueguen 

 "have had occasion 

 to observe this phos- 

 phorescence in 

 Xylarias kept under 

 a bell-jar, as well as 

 in the mycehum ob- 

 tained in cultures 

 shortly to be de- 

 scribed. The phos- 

 phorescence, as 

 Ludwig remarked, 

 is exclusively con- 

 fined to the myce- 

 lium. In both 

 instances it seemed 

 very feeble and in 

 no way comparable 

 in intensity with 

 that one observes 

 so frequently during 

 the warm season on 

 fish and other marine 

 animals exposed to 

 the air. The glow 

 of the Xylaria is 

 white tinged with 

 blue, and one can 

 only perceive it clearly in complete darkness. It is only to be 

 observed at certain periods in the life of the fungus, e.g. when the 

 mycehum is in full development. Old cultures no longer exhibit it." 

 It thus appears that, as a result of studies with pure cultures, 



Fig. 177. — Fruit-bodies of Xylaria Hypoxylon, the 

 Stag's-horn Fungus, growing from the bark of a 

 dead tree. The white and bifurcated ends of the 

 branches are covered with conidiophores whicli 

 produce vast numbers of conidia. The latter dis- 

 perse as a visible cloud wlien the branches are 

 suddenly jarred. The black lower parts of the 

 branches are persistent and develop beneath their 

 surface numerous perithecia containing asci and 

 ascospores. The mycelium of the fungus, grown in 

 pure cultures, was found by Gueguen to be luminous 

 and by Molisch to be non-luminous. Photographed 

 in Yorkshire, England, by A. E. Peck. Natural 

 size. 



VOL. III. 



2 E 



