138 EFFECTS OF RADIATION ON FUNGI 



stipticus, Pleurotus incandescens y P. facifer, P. gardneri, P. igneus, 

 P. noctilucens, P. olearius, P. phosphor eus, P. prometheus. The 

 rhizomorphs of Armillaria mellea and the sclerotia of Colly bia 

 tuberosa and C. cirrhata are luminescent. Among other species 

 claimed to be luminous are Fomes annosus, Poly poms sulphur ens, 

 Pomes piui, Colly bia longipes, Corticium coerideum, Dictyophora 

 phalloides, and Xylaria hypoxylon. 



The mycelium and pilei of Pamts stipticus in North America 

 are luminous, whereas those in England are non-luminous [Buller 

 (1924)]. Dried fruit bodies do not glow, but, if revived by 

 moistening, they again emit light. Not only moisture but also 

 favorable temperature relations are necessary for luminescence. 

 The minimum temperature for P. stipticus is —2° to — 4° C, the 

 maximum 35° to 37° C, and the optimum 10° to 25° C. 



Oviphalia flavida is of special interest because it has long been 

 known to be the cause of a serious leaf disease of the coffee tree 

 in the American tropics. Buller (1934) discovered that the lesions 

 induced by O. flavida are luminous and reported that they may 

 be seen in the dark at a distance of 6 to 10 ft. In culture the 

 mycelium too is luminous. This organism is capable of forming 

 peculiar structures called gemmifers and gemmae if the stimulus 

 of alternating day and night is provided. 



Luminosity in these fungi, as in other luminous organisms, is 

 the result of an oxidative change within the cells, luciferin bein^ 

 acted upon by the enzyme luciferase in the presence of oxygen. 

 Apparently this enzyme has not been extracted from fungi, nor 

 has it been demonstrated to be capable of functioning apart from 

 living cells. 



INHIBITORY EFFECTS 



Exposure of fungi to sunlight has long been known to modify 

 their rate of growth. If the total illumination is small, growth 

 may be retarded, but with larger amounts death may ensue. This 

 matter appears to have been given rather extensive study, as Smith 

 (1936) has indicated. 



It would be anticipated that not all species of fungi are equally 

 sensitive to sunlight. Abundant evidence in support of this con- 

 clusion from comparative studies is not available. Fromme (1915) 

 noted that the germ tubes of urediniospores of Puccima rhamm 

 are negatively phototropic and mentioned that a similar reaction 



