New Species of Exoascaceae. 



I5Y 



S. Kusano. 



With Plate I. 



Taphrina truncicola Kusano n. sp. 

 (Figs. 1-6). 



This fungus was discovered by me some years ago at Nikko, but owing 

 to its imperfect development, its specific name has been still unknown. 

 Early in this summer, having a good occasion to examine some fresh 

 specimens of the mature form of this fungus, I was able to come to the 

 conclusion that it was a species of Taphrina hitherto undescribed. The 

 diagnosis of this new species may be given as follows : 



The fungus attacks the buds of Prunus incisa Thunb. and its myceli- 

 um inflicts much injury upon the axial portions of the young shoots, 

 causing hypertrophy and distortion (Fig. 1). In the stem the effect of 

 hypertrophy is exhibited most conspicuously at the basal portion, the dia- 

 meter increasing up to 1 cm. While the growth of the stem is generally 

 stopped within the limits of 4-10 cm. the petioles of the leaves develope to 

 so extraordinary an extent as they sometimes even attain to 5 cm. in length 

 and acquire the appearance of hypertrophied stems u) (see Fig. 1). But 

 the blades beyoud these infected portions, being free from the attack of 

 fungus mycelium, may develope quite as normal. They remain freshy 

 until the stem and petioles below them have been utterly destroyed by 

 the fungus. 



When the flower bud is attacked by the fungus it will give rise to the 

 morbid inflorescence of the similar deformation. The normal inflorescence of 

 Prunus incisa consists of a few long stalked flowers arranged on a compara- 

 tively short axis which is provided with a green round leaflet on each node. 

 The fungus mycelium spreads over its axial portions — axis and flower stalks 

 — as in the case of the shoot, but never over leaflets and flowers which 

 both do not differ materially from normal ones (Fig. 2). 



(1) The petiole of the normal leaf is less than 1 cm. in length. 



