ENDOTHIA PARASITICA AND BELATED SPECIES. 69 



species of Quercus, chiefly Q. prinus and Q. alba, only one case has 

 been noted in which the fungus assumed a typically parasitic role. 

 The data in this case may be summed up as follows : Four inocula- 

 tions were made May 27, 1914, on a small tree of Quercus alba* This 

 tree was suppressed, and although when cut down it showed about 

 30 annual rings it was only 16 feet high and about 2 inches in diam- 

 eter. It was in a moist, shady locality close beside a stream, and in 

 spite of its small size was apparently healthy. The inoculations 

 were made in the usual way from a culture of E. parasitic on corn 

 meal. On August 1 it was noted that all four inoculations were pro- 

 ducing pycnidia, and in at least one case typical fans had been 

 developed. On October 15 all four cankers had more than half 

 girdled the seedling. No observations were made during the winter, 

 but at the time the leaves had reached half the normal size, in the 

 spring of 1915, the tree was completely girdled. On July 1 this tree 

 presented an appearance closely similar to that of a small chestnut 

 tree girdled by EndotMa parasitica. All the leaves above the point 

 of inoculation were dead and remained attached to the branches. 

 Below the girdled portion, water sprouts had developed, as has been 

 frequently described for chestnut trees affected with E. parasUica. 

 Cultures made from this tree showed the fungus to be typical of 

 E. parasitica. Whether this case of parasitism was due to unusual 

 virulence on the part of the fungus or to unusual susceptibility on 

 the part of the host is, of course, merely a matter of conjecture ; the 

 latter alternative seems, however, somewhat more probable, as other 

 inoculations with this strain of the fungus on Q. prinus and Q. alba 

 failed to show similar results. 



In addition to the above, a somewhat similar observation has been 

 made by the writers near Amherst, Mass. In connection with other 

 work, a sprout of Quercus prinus about an inch in diameter was 

 inoculated with Endothia gyrosa on July 15, 1914. When this inocu- 

 lation was made the tree was partly (about one-fourth) girdled. 

 E. gyrosa developed normally and by October 1, 1914, had produced 

 several pycnidial stromata. No change was apparent when the inocu- 

 lations were examined in May, 1915. 



E. parasitica was abundant in the region, however, and apparently 

 gained entrance through the cuts originally made, for when the plat 

 was next visited, August 17, 1915, the sprout appeared quite dead, 

 though still retaining its full-sized dead leaves. Further examina- 

 tion showed numerous pycnidia of E. parasitica in addition to those 

 of E. gyrosa near the region of the original inocul ation. The pycnidia 

 of E. parasitica were on all sides of the stem, while those of E. gyrosa 

 were confined to the portion above the cuts made in inoculating. The 

 mycelial fans typical of E. parasitica were abundant also. These 



