168 



Mycologia 



then spreads over the branches, finally covering the entire tree 

 down to the roots. The infection occurs in winter and early 

 spring, mostly on the wounded or dead part of shoots, which 

 gradually become rough, dry and brown, and finally crack with 

 irregular elevated spots appearing on the surface — the stromata 

 of the fungus. Loose mycelia from the stroma connect the tissues 

 of the host and the fungus bodies. The pycnidia first appear on 

 the stromata as depressed globular flasks, 1.5 X -6 mm., with 

 colorless, obtuse, slightly curved pycnospores 2.85-8.75 X 0.88- 

 1.75 /x on short, branched conidiophores. The perithecia, ar- 

 ranged at the bottom of stroma, 15-16 in one group, are flask- 

 shaped with long necks about twice or three times the length of 

 the perithecial body which measures 1 50-300 //, in diameter; asci 

 very fragile, soon disappearing, cylindric or clavate, more or less 

 curved, sessile or very short stalked, 32^52 X8-iO/x octospored ; 

 ascospores generally in two rows, occasionally irregular or one 

 row, cvlindric. obtuse, curved, smooth, hvaline, very slightly Dal** 

 brownish when mature, 10-18 X 2 ~4/^ germinating in 20-24 

 hours, either in distilled water or on culture media. 



This " Tachigare " or dieback disease first appeared in Hok- 

 kaido about 1910 and seriously damaged Paulownia, first in 1913 

 and 1914 when many old trees were killed. In 191 5 the disease 

 spread all over Hokkaido, and in one case about 3,000 trees at the 

 same place were attacked. 



For its prevention the trunks of the trees should be wrapped 

 with straw in winter so as to prevent freezing or wounding. 

 Bordeaux mixture should be used as a spray on the trees in early 

 spring. 



Ophiochaeta graminis (Sacc.) K. Hara n. comb, in Byochu- 

 gai Zasshi- (Journ. of Plant Protection) 3 5 : 342-345. May, 

 1916. (Japanese.) 



This fungus, commonly called Ophiobolus graminis, is known 

 as a cause of foot-rot of wheat and barley in France, Belgium, 

 Germany, and Japan. The author discovered a similar disease on 

 rice-plant caused by the same fungus which he proposes to trans- 

 fer to Saccardo's genus Ophiochaeta, on account of the existence 

 of bristle hairs on the perithecium. In the case of the fungus 

 attacking the rice-plants the perithecia are somewhat smaller, i. e., 

 240-480 /x diameter, and the ostiolum 1 2-280 /x in length and 7-8 m 

 across, but the asci and ascospores are nearly the same as de- 

 scribed from other plants, %. e., asci 80-120X8.5-16^ and asco- 

 spores 27.1-104 X 3- 2 -4^. 



