260 THF BOTANICAL MAGAZINE. [Vol. xxix. No. 346. 



initiation of the teleutospores in Chrysomvxa expansa takes 

 place in the middle portion of Honshu in about the first part 

 of June, while in Hokkaido from the latter part of June to about 

 the middle of July, varying according to the difference in the 

 altitude of the locality. 



On the specimens collected in the latter part of June on 

 Rhododendron chrysanthum, the uredo-sori with the spores still 

 retained, as well as already shed, could be recognized. The 

 sori are roundish or more or less elongated in shape, and soli- 

 tary or in small groups. On one side of or surrounding the uredo- 

 sorus or sori a group of the teleutospore-sori is generally to 

 be found. On the leaves of R. brachycarpum yellowish spots 

 are observable from August and September of the previous year, 

 but we have not seen so far any sign of the formation of the 

 uredo-sori during the autumn. Unlike Chrysomvxa Rhododendri 

 (4. 7. 8), our species seems to form its uredospores only in 

 spring and not both in autumn and spring. 



The uredospores are variable in shape, ranging from oval 

 to ellipsoidal, ovate-oblong or irregular. They are larger than 

 in the case of Chrysomyxa Rhododendri (4, 7), measuring 22— 

 38 fi in length and 16-24 /u in diameter. The membrane is 

 prominently aud densely warty, the length of the projection 

 being 1—2 ju. 



The teleutospore sori are formed in a close group on the 

 undersurface of a yellowish red or brown spot, which turns to 

 a blackish color in a later season. The size and shape of the 

 maculae are variable. They are roundish, elliptical or irregularly 

 angular, the margin being always limited by veinlets. Dietel 

 mentions that the largest spot has the diameter of 15 mm. Of 

 our materials, the largest we could find is 11 x 9 mm. and the 

 smallest lxl mm. the average size being 6x5 mm. 



The teleutospore-sorus projects conspicuously out of the 

 tissue of the host and expands into a subglobose or ellipsoidal 

 head with a narrowed short stalk. In general, the sori are 

 more or less closely and evenly disposed in a macula ; while 

 some having coalesced form allantoid or irregular masses. The 

 heads, when seen from above, measure .33-.60 mm in length 



