10 p M—u y5' i> t c^ m m^ 



reaching tu pallisade cells, whose chloroplastids are destroyed. The conidiophores 

 are thickly arranged parallel to each other and at right angles to a cushion of 

 stroma, from which they arise. They are simple, straight or slightly curved, 

 hyaline, smooth and unseptated, with granular contents. They measure 18-25 

 (rarely 30) x 3-3.5 //. 



A conidium is produced on the apex of the conidiophore. The spore is fdiform 

 or clavate-cylindrical in shape, straight or mostly curved on one side, and rounded 

 at both ends. They are smooth, hyaline and guttulate. AVhen the conidia are 

 stained with iodine solution or other coloring solutions, it will be clearly observed 

 tiiat the raajority of them consist of one to three, rarely four cells. Wlien it is 

 mounted in water or potash, these septa may often be overlooked. Tlicy measure 

 26-67.5x2-3.5 li. 



Placed in a drop of water or the decoction of the host-plant, the spores germi- 

 nate within 24-50 hours, throwing out one or two germ-tubes at or near the ends. 

 The germinating hyphae arc hyaline, about 2fj. in width and occasionally swollen 

 in irregular shape. 



Nomenclature of this Fungus. 



From the morphological characters of the spore and hymenium, we may easily 

 recognize our present fungus to be a species of Cylindrosporium. Up to tlie present 

 time, I have not yet been able to obtain the ascosporbus stage of the fungus both 

 in its natural state as well as in its pure culture. 



No species of Cylindrosporium parasitic on the species of Dioscorea has yet 

 been recorded in mycological literatures. Considering the fungus as a new species, 

 the following diagnosis is given. i. 



Cylindrosporium Dioscoreae IMiyabe et S. Ito. 



Spots amphigenous, at first nnbordered, small, yellowish, at h^st bordered, brown 

 or blackish brown, scattered or gregarious, roundish, polygonal or irregular, often 

 confluent. 



Acervuli mostly epiphyllous or hypophyllous, also on vines and petioles, minute, 

 scattered or gregarious, roundish, somewhat elongated on vines, slighty raised, at 

 first covered by the cuticle, brownish or dark brown, finally erumpent above, tlien 

 whitish, fle.>hy-colored or pinky white. 



Conidiophores simple, straight or slightly curved, smooth, unseptated, granulate, 



