39 



lightning the thought comes in this h\pothesis that in the stigma secretion and in the honey 

 of the blossoms the natural saprophytic substrata are given in which the smut spores germi- 

 nate, are propagated, and penetrating with their germinating tubes through the canal of the 

 style, reach the embryonic seed. Here again we find an obvious explanation for the facultative 

 parasitism already indicated and for the first exceedingly easy nutrition of smut spores in all 

 possible nutrient solutions. Substrata for the saprophytic nutrition of these fungi are found not 

 only in tlTe soil but also in the blossoms of plants fertilized by insects which are very often 

 attacked liy smut fungi. The anther smut of these has as yet been brought forward as one, 

 and indeed as the most pregnant and interesting case for our investigation. 



Having discussed these preliminary questions we will turn now to the practical experi- 

 ments. These experiments were carried out first of all with Melandryum album. The pistil- 

 late blossoms of these plants were infected with the smut dust from the anthers of staminate 

 blossoms'. A suitable brush was substituted for the insect proboscis and the dissemination, 

 that is, the infection of the stigma, was carried through even to the deeper parts of the ovule 

 just as the introduction of the spores is thought to take place by means of the insect proboscis. 

 That infection had taken place was undoubted, but unfortunately the harvesting of seed from 

 the infected blossoms was frustrated. Plants of Melandryum album were to be found only 

 outside of Breslau. Therefore inoculation could be made only here and the infected plants could 

 not be constantly observed. They had been cut down when we wanted to harvest the seed. 

 In order to avoid experiences like these, healthy and infected Melandryum plants were grown 

 in the experimental garden. Inoculation could be carried through in the garden and the plants 

 constantly watched. Unfortunately new disturbances became apparent here which could not 

 have been previously suspected. When the capsules had become ripe, it was seen that, except 

 for a small remnant, all of the seed had been eaten up by maggots. This remnant was sown 

 in the following year. Among the plants thus grown was found a number of smutted indi- 

 viduals. Further experience showed that a natural infection can be obtained with certainty, by 

 means of butterflies, when healthy pistillate plants of Melandryum are grown in immediate 

 proximity to smutted stalks. Even microsco pic investigation of the stigmad ' in these plants 

 showed that almost without exception they had been dusted over with smut spores, which 

 observed microscopically, may be seen to germinate on the stigma and to develop further. The 

 seed subsequently harvested from such pistillate blossoms and sterilized, but which neverthe- 

 less was strongly injured by insects, furnished as much as 20% of smutted plants in the sep- 

 arate hosts. Their diseased condition could be explained only by the previous infection of the 

 blossoms. We must be s^atisfied for the present with these details. Investigations like these 

 cannot be completely exhausted in a few years, they need to be continued for many years if 

 they are to furnish results sufficient for all time. 



(1) In the vicinity of Breslau, we have found only staminate blossoms which had been attacked in 

 the anthers by Ust. Antherarum. It has been stated, however, by older authors (TULASNE, GIARD, 

 MAGNIN and others), and held until most recently, that there are also androgynous blossoms. From this 

 it is assumed that the development of these anthers which are always smutted is brought about by the 

 influence of the fungus. 



