. ^ 



378 BOTANICAL GAZETTE [jtJxNE 



■ 



may be easily washed by rains to the neighboring leaves and cause 

 infection. 



Pure cultures on artificial media were made from all of these 

 difTerent stages and the resulting colonies compared. In all cases the 

 same mycelium and the same colony were produced. The mycelial 

 threads are i-io/^ in diameter, the small ones being nearly con- 

 tinuous^ while the larger ones are closely septate. The colony 

 characters agree perfectly with those given by Klebahn. Both 

 conidia and ascospores germinate readily, the latter, however, only 

 from the large cell. The small cell was never seen to send out a germ 

 tube. 



r 



This fungus {Gnomonia veneta) also occurs on three other hosts at 

 least; Quercus alba, Q. veluluia, and Q. coccinea. In 1890 Halsted 

 (17) described the disease occurring upon white oak as due to Gloco- 

 sporium ncrvisequum, but there has always seemed to be some question 

 of it. The anthracnose of white oak generally is said to be due to G. 

 canademe E. & E. Dead white spots from a few millimeters to a 

 centimeter in diameter are formed, generally scattered over the leaf, 

 though sometimes the tip of the leaf is killed, and sometimes the spots 



follow down the veins. 



do not differ fmm tVinc. 



ules and conidia {fig. 7) 

 The two were studied in 



pure cultures, and the germination and the colony characters seemed 

 to be the same. To make sure, however, that the fungus was the 

 same as the one on sycamore, diseased leaves were put between wire 

 netting and placed out of doors to winter in order to obtain the as- 

 cigeral stage. As on the sycamore, the fungus spread over the dead 

 leaf and in late winter produced perithccia in abundance. The char- 

 acters of perithecia, asci, and spores are the same as in those produced 

 on the sycamore, w^ith the exception of the length of the necks of the 

 perithecia. OutHne drawings of the asci and spores are shown in 

 figs. 21 and 22, so that thev mav be comnared with those from the 



svcamore 



much 



those on the sycamore, some being as long as the body or even longer. 



some 



were almost wanting. This single difference does not seem to me 

 to be sufficient to separate the forms as distinct species. The length 



