334 Journal oj Agricultural Research voi. iv. No. 4 



INOCULATION EXPERIMENTS 



To prove the pathogenicity of A. clematidina, mycelium from pure 

 cultures was inoculated into stems of C. paniculata and C. jackmanni. 

 In all cases lesions were produced, while the checks remained normal. 

 From such lesions the fungus was reisolated, and, when again inoculated 

 into either host, typical lesions were produced. In all, four sets of 

 inoculation experiments were carried out at various times, making from 

 3 to 10 inoculations on each of 32 plants. Inoculations on succulent 

 Stems caused the vines to wilt in four days, while in one case an inocula- 

 tion on a woody vine 6 mm. in diameter required 47 days to kill the plant. 

 Pycnidia were produced on all lesions. 



Plants of C. paniculata were sprayed with sterile water containing 

 spores of A . clematidina and then kept under bell jars for two days. On 

 the third day the leaves showed water-soaked spots of various sizes, 

 while the checks, which had been sprayed with sterile water, remained 

 free from disease. To test the effect of temperature on infection, two 

 plants were sprayed with the same spore-laden water and then subjected 

 to different temperatures: 23° C. and 10° C. At the end of five days the 

 plant kept at 23° showed 45 leaf spots, while the plant kept at 10° showed 

 but I spot. 



Spores placed on the lower surface of the leaves produced more spots 

 than those placed on the upper surface. Typical lesions w-ere also pro- 

 duced on the roots by inoculating them with the mycelium from a pure 

 culture. 



The A. clematidina isolated from C. panictdaia was inoculated into 



growing stems of bean, pea, muskmelon, pumpkin; into stems, petioles, 



and fruits of eggplant (var. Black Beauty) ; and into the young shoots 



of elm. In all cases negative results were obtained. On most of these 



plants pycnidia were produced on the tissues killed in making the wound, 



but in no case did the mycelium penetrate the healthy tissues and form 



a lesion. 



TAXONOMY OF THE FUNGUS 



Arthur (1) observed a species of Phoma, possibly P. clematidis, on 

 clematis, but on consulting the original notes made by him it is clear that 

 he had a fungus different from that found bv the writer. On but one 

 occasion has Phoma sp. been found and that was a saprophyte on the 

 leaf of C. paniculata. It was isolated in pure culture, the mycelium 

 inoculated into the stems, and the spores sprayed on leaves, but in no 

 case were lesions or leaf-spots produced. 



Saccardo (11) notes A. clematidina, A. vitalbae, A. indusiata, and A- 

 davidiana as occurring on various species of clematis, and their chief 

 point of difference is in the size of the spores. The writer has examined 

 the specimens of A. clematidina Thumen on C. virginiana collected by 

 Mr. J. J. Davis in Wisconsin and distributed in Fungi Columbiani No. 



