ihiccd in tlic culture-media I have used, while the chlainj'dospore production is 

 generally conspicuous. On the soy agar and apricot-decoction agar media, the 

 aerial growth of the mycclivun is comparatively vigorous, and there is at the same 

 time some growth in the substrata. The chariicters on different media are as 

 follows : 



a. Cn/iiiivs on the leaf-decoction agar of Lnpinm polyphyllits. The mycelium begins to spread from 

 the infected portion at first as a white or li;;lit lirown ^veft and spreads rapidly toward the ed.;e. The 

 mycelium is npt to creep on the surface of the medium, and tlie aerial mycelium is very scanty. The my- 

 celium turns .;;radually hrown in color. After a while, numerous small black dots are seen in the peripher- 

 al portion of the medium, where the creei>ing myceliumis thinly formed. Under a microscope, I have prov- 

 ed those dots to be the knots of chlamydospores. The conidiospores are rarely produced in old cultures. 



b. Cultures on tite corn-meal agar. The mycelial .;^rowth on the surface of this medium is sometimes 

 entirely lacking or very scant. The mycelium grows entirely in the medium and it presents macroscopical- 

 ly as dense radiating groups of many grayish-lilack fine stripes or lines. On these stripes or lines are found 

 numerous black spots, which are the knots of the chlamydospores. The oonidial production is, however, 

 very scint. 



c. Cultures on the apricot-decoction agar. On this medium, the fungus grows vigorously and caused 

 it to become more or less darkened. At first a white aerial mycelium grows actively and after a while its 

 color gradually turns gray and sometimes blackish gray. The knots of the chlamydospores are alfo more 

 or less produced on the hyphae growing in and on the medium. 



d. Cultures on the soy agar. The us? of the Japanese soy or shoyu as a cultural medium for fungi was 

 at first proposed by Prof. M. MlYosHl CO-") in 1S95. On this medium, a velvet-like lirownish-gray mycelial 

 layer is produceil within a week after inoculation. The chlamydospores are produced abundantly. The 

 conidiospore is not produced even on the medium of two months old. 



7. Chlamydospores of the Causal Fungus 



The chlamydospores are most abundantly produced in the corn-meal agar 

 cultures, although in other cultures they are also formed to more or less extent. 

 The hx'phac, from which the chlamydospores are to be formed, turn gradually 

 brown or light brownish gra)- in color, accompanied by the process of the divi- 

 sion into a series of numerous short ellipsoidal cells. These cells transform at 

 once into the chlam\'dospores first by their swelling and then by the thickening 

 of their cell-walls. Consequently the chlamydospores thus formed are usually 

 arranged in a chain, although a single chlamydospore is rarel}'' produced inter- 

 calarely in the hy[)hae. Our fungus is, however, characteri/;ed b\- the formation 

 of the knots of the chlamydo.spores, having remarkable forms. .\ knot of the 

 chlamydospores consists of a mass composed of from a few to thirty cells having 

 a thick and deep brownish-black cell-wall and granular contents. The knots 



