THE INFLUENCE OF THE MYCELIUM OF USTILAGO VIOLACEA. 115 



granted that when a parasite attacks all the reproductive organs 

 produced by a given plant, as when all the ears of a Wheat plant 

 are affected with bunt or smut, that the parasite has gained 

 admission into the host-plant at some early period of its exist- 

 ence ; with the above-named parasites this is perfectly true, and 

 it is most likely to be the case with the majority of other plants 

 all of whose shoots produce infected flowers. 



In the summer of 1888 I transplanted into my garden a 

 healthy female plant of Lychnis vespertina. The object I had 

 in view was to see if I could discover how and when Ustilago 

 violacea effected its entrance into the Lychnis, and also to 

 learn whether the U. violacea onL. diurna and on It. vespertina 

 were the same species. My idea was that the spores from the 

 diseased anthers were carried with the pollen, either by insects 

 or otherwise, to the stigmata of healthy plants, and that the 

 resultant seeds would produce plants infected with the Ustilago. 

 For the purpose, then, of obtaining artificially infected seeds, the 

 healthy female plant of L. vespertina was placed near a number 

 of diseased plants of L. diurna. After due time the L. vespertina 

 became established and produced healthy flowers, the long- 

 pointed stigmata of which projected well beyond the tube of the 

 corolla. Being sizeable objects and white in colour, it was very 

 easy to apply the Ustilago spores to them. In due time the seeds 

 ripened, and with much care and ceremony were duly planted. 

 The seedlings which came were, however, very few in number 

 and perfectly healthy ! The parent plant was not removed, but, 

 to my great astonishment, when it flowered this spring (1889) it 

 had changed its sex ; not a single female flower has it produced 

 this year, but etery blossom has contained anthers only, every 

 one of which has been affected with U. violacea. It would be 

 unwise to attach too much importance to a single case, but the 

 probability of error in this case is very small. It was the only 

 plant of L. vespertina in my garden, and its sex had been made 

 the subject of special and frequent observation. We have here, 

 therefore, an illustration that the presence of the mycelium of 

 U. violacea can change a female into a male plant, and further, 

 that the fungus can sometimes at least effect an entrance into 

 an adult plant. The mode by which this has been accomplished 

 is unknown to me, and I have no intention of theorising upon it. 



In the same garden have been grown six plants of L. diurna, 



i2 



