OMPHALIA FLAVIDA 439 



Vanterpool and I ^ took the leaves of Bryophyllum, Neriiim, 

 Ficus, and Plumbago which we had artificially infected with Omphalia 

 flavida into the dark room and there observed that the leaf-spots on 

 all the four kinds of leaves emitted light. 



The observations on luminosity so far recorded were all made 

 with a strain of Omjjhalia flavida of Trinidad origin. In 15)28, 

 another strain, of Porto Rican origin, was examined and found to 

 be equally, or perhaps even more, strongly luminous. The light 

 emitted by the mycelium of Porto Rican origin, when the mycelium 

 is growing on bread in a conical flask of 400 cc. capacity, was 

 sufficiently strong to permit of the reading of large print with letters 

 6 mm. high. 



Four leaves of Nerium Oleander which had been inoculated with 

 the Porto Rican strain of Om'phaUa flavida showed infected areas 

 which were irregularly elliptical and about two inches long {cf. Figs. 

 201 and 202, pp. 402 and 403). On examining these leaves in a 

 dark-room I was able to detect the leaf-spots by their luminosity 

 when the leaves were 12 feet distant from my eyes. A nearer view 

 of the leaves revealed that the leaf-spots were beautifully defined 

 by the light which they gave out. On examining the leaf-spots 

 with a hand-lens, I clearly perceived that the luminosity was 

 not confined to the mycelium in the leaf but extended also to 

 the gemmae.^ The young gemmae could be seen as bright 

 spots. Some germinating gemmae which had rested for a few 

 hours on a fresh Oleander leaf had the appearance of tiny 

 stars. On the other hand, no luminosity could be detected in 

 older cultures as coming from the little agarics which produce the 

 basidiospores. 



The discovery that the mycelium of Omphalia flavida growing 

 in the leaf-spots of living leaves emits light has provided a means of 

 diagnosing the American C'of[ee-leaf disease in the dark. Unfor- 

 tunately, owing to my great distance from those parts of America 



^ A. H. R. Buller and T. C. Vanterpool, " The Bioluminesoence of Omphalia 

 flavida, a Leaf-spot Fungus," Phytopathology, Vol. XVI, 1926, p. (33. 



2 In the communication of Buller and Vanterpool {loc. cit.) it was stated that the 

 gemmifers and sporophores " give out no light whatever." This statement, in so 

 far as it applies to gemmifers, is erroneous ; for, as here recorded, it has been found 

 that the gemmae are luminous. 



