ocfciws.] K. MIYABE.—ON CHRYSOMYXA EXPANSA. 



known by the name of P. ajanensis var. microsperma Mast. 

 (3). Thev belong to the Section Omorica, the flat-leaved spruces 

 (3). 



By the kindness of Prof. Kusano, the author was able to 

 examine the type specimen of Peridermium Piceae-hondoensis and 

 thus to compare it with our Ochiai specimens. As had been 

 expected, they were exactly the same. 



Aecidia are formed on the undersurface of the leaf arranged 

 in a series on both sides of the midrib. The portion affected 

 turns to a yellow color and is sharpW limited from the green 

 healthy portions. In most cases, the discolored portion forms 

 a distinct zone at about the middle of the leaf. The aecidia are 

 tubular, which are more or less flattened laterally, or several 

 of them coalescing form flattened sack-like bodies elongated in 

 the direction of the long axis of the leaf. The}' are 0.4-0.7 mm 

 high, and 0.35-1.6 mm wide in the longer diameter. The peri- 

 dial wall is white, inflated, rather rigid, and is torn at the 

 apex into shallow irregular pieces, and is also cut into a few 

 rather deep lobes. The large lobes are reflexed, exposing the 

 orange red aecidiospores. 



Peridial cells are rhombic or oblong in shape, 25—55 fx in 

 length and 15-28 ;i in width, thick walled, densely and finely 

 verrucose. Aecidiospores are subglobose or ellipsoidal, 19-22 // 

 long and 14—20 /j. wide. With the exception of a smooth elon- 

 gated spot, the entire surface of the spore is rather thickl\ r and 

 finely warty. Some of the warts are in the form of short irre- 

 gular ridges. 



In order to prove the genetic relation between Chrvsomvxa 

 expansa and Peridermium Piceae-hondoensis, the following infec- 

 tion experiment was carried out in the spring of 1913. For 

 the purpose, a large number of young seedlings of Rhododen- 

 dron brachycarpum, whose leaves had already been infected, 

 were collected at Ochiai in the summer of the previous year. 

 They were all carefully potted and placed in a shady cool 

 place in our Botanic Garden. 



On May 21, we noticed the fully developed teleutospore sori 

 on some potted plants. This was about a month earlier than 



