1904.] 



Notes on the Japanese Fungi. 



I. UREDINE/E ON SOPHORA. 



BY 



S. Kusano. 



With Plate I. 



Uromyces truncicola P. Henn. et Slur. 

 (Engl. bot. Jahrb. XXVIII. 1900. p. 260) (Fig?. 2. 4). 



Sophora japonica is very often attacked l>y two kinds of Uromyces, 

 of which Uromyces truncicola, cause of the canker growth of the tree, 

 ultimately brings it to destruction. So far as my observations go, no older 

 stock of this tree has ever been found in Tokyo till now, whose stems 

 or branches are entirely free from this dangerous fungus. Any old tree 

 carries generally several hundreds of cankers, small or large according to 

 the size of stems or branches on which they occur. Branches once attacked 

 by this fungus are gradually destroyed by various causes which may fall 

 upon them during long intervals of their growth. It is surely clue to this 

 reason that the old trees cultivated in the Botanic Garden of Tokyo and 

 Komaba (10 in number), having lost the greater part of their crown, are 

 now gradually approaching to death. 



When young, a canker produces every year on its peripheral portion 

 a large mass of teleutospore.s, which, forming large irregular sori, upheaves 

 the overlying bark and bursts out from the fissure of it. 1 The spores 

 are easily swept away by tin or dew, so that they are found finally only 

 along the under side of dach branch, forming a thick, black to brownish 

 coating. They germinate in the next spring and produce numerous 

 sporidia, which infeSt immediately the young stem, causing a slight thicken- 

 ing and discolouration around the infected point : this constitutes the 

 primary generation of the fungus (Fig. 2 a). At iirst, appear in this place 

 numerous pyenidia which are replaced soon after by aggregated teleutosori 

 of small size. 2 With the growth of the stem the intercellular mycelium 

 spreads here and there, and giving rise to the abnormal growth, especially 

 of the cortex causes the spindle-shaped canker. The teleutosori are formed 



1. In an old canker the fungus remains sterile. 



2. On this account the fungus may be included to Microuromyces. 



