OMPHALIA FLAVIDA 441 



Agriculture at Bogota, wrote a letter to the Vice-consul of New 

 Granada (Colombia), quoted by Dr. Ernst ^ in another letter to 

 Nature, in which, after describing the Coffee leaf-spots and the 

 yellow gemmifers which appear upon them, he adds : " This fungus 

 is said to be phosphorescent at night ; and in places where it is very 

 common a phosphoric smell is noted." That the Coffee leaf-spots 

 should appear to be luminous in plantations after dark is exactly 

 what might be expected in view of the laboratory observations of 

 Vanterpool and myself and the Porto Rican observations of Pro- 

 fessor Miiller, but the idea that the fungus gives out a phosphoric 

 smell is doubtless an accretion invented by the mythopoeic faculty. 

 Omphalia flavida, it is true, is odoriferous, but its scent is faint and 

 pleasant, reminding one of apricots ^ ; and, as stated in the discussion 

 of bioluminescence in Volume III,^ there is no reason to believe that 

 the emission of light by fungi has any special relation with the 

 element phosphorus. 



There is another leaf-spot disease of Coffee caused by Sclerotium 

 cojfeicola which will be treated of in the next Section. Here it is only 

 necessary to state that a comparison of artificial cultures made in 

 the Winnipeg laboratory in the dark showed that, whereas the 

 mycelium of Omphalia flavida is luminous, the mycelium of 

 Sclerotium cojfeicola is non-luminous. The luminosity criterion, 

 therefore, should enable a phytopathologist to determine whether 

 a particular Coffee leaf-spot is or is not caused by Omphalia 

 flavida. 



Omphalia flavida is not the only species of Omphalia which is 

 luminous, for O. Martensii emits light also. Omphalia Martensii 

 was described by Hennings * in 1893. This fungus grows on roots 

 on the ground in Borneo ; and in March, 1863, near Bengkajang, 

 it was observed to be luminescent by Professor O. Martens, a zoo- 

 logist who had accompanied a Prussian expedition to eastern Asia. 



1 A. Ernst, " Coffee-Disease in New Granada," Nature, Vol. XXII, 1880, p. 292. 



^ The scent can be detected when the mycelium has just covered a malt-agar 

 Petri dish and is producing gemmifers. 



3 These Researches, Vol. Ill, 1924, p. 364. 



^ P. Hennings, " Einige neue und interessante Pilze aus dem Konigl. Botanischen 

 Museum in Berlin," Hedivigia, Bd. XXXII, 1893, pp. 63-64, PI. VII, Fig. 3. I am 

 indebted to Mr. L. C. C. Krieger for calling my attention to this paper. 



